Item 15. EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.

*(a)*Financial Statements filed as part of this report:

			PAGE
IRON MOUNTAIN INCORPORATED
Report of Independent Registered Public Accounting Firm (PCAOB ID No. 34)			66
Consolidated Balance Sheets, December 31, 2023 and 2022			68
Consolidated Statements of Operations, Years Ended December 31, 2023, 2022 and 2021			69
Consolidated Statements of Comprehensive Income (Loss), Years Ended December 31, 2023, 2022 and 2021			70
Consolidated Statements of Equity, Years Ended December 31, 2023, 2022 and 2021			71
Consolidated Statements of Cash Flows, Years Ended December 31, 2023, 2022 and 2021			72
Notes to Consolidated Financial Statements			73
Financial Statement Schedule III—Schedule of Real Estate and Accumulated Depreciation			127

*(b)*Exhibits filed as part of this report: As listed in the Exhibit Index following the Financial Statement Schedule III-Schedule of Real Estate and Accumulated Depreciation.

			IRON MOUNTAIN 2023 FORM 10-K			65

Part IV

REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

To the shareholders and the Board of Directors of Iron Mountain Incorporated

OPINION ON THE FINANCIAL STATEMENTS

We have audited the accompanying consolidated balance sheets of Iron Mountain Incorporated and subsidiaries (the "Company") as of December 31, 2023 and 2022, the related consolidated statements of operations, comprehensive income (loss), equity, and cash flows, for each of the three years in the period ended December 31, 2023, and the related notes and the schedule listed in the Index at Item 15 (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2023 and 2022, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2023, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control — Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 22, 2024, expressed an unqualified opinion on the Company's internal control over financial reporting.

BASIS FOR OPINION

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

CRITICAL AUDIT MATTERS

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

66			IRON MOUNTAIN 2023 FORM 10-K

Part IV

GOODWILL - ASSET LIFECYCLE MANAGEMENT REPORTING UNIT - REFER TO NOTE 2.L. TO THE FINANCIAL STATEMENTS

CRITICAL AUDIT MATTER DESCRIPTION

The Company’s evaluation of goodwill for impairment involves the comparison of the fair value of the reporting unit to its carrying value. The Company determined the fair value of the Asset Lifecycle Management reporting unit based on the present value of future cash flows (the "Discounted Cash Flow Model"). The determination of the fair value using the Discounted Cash Flow Model requires management to make significant assumptions related to future revenue growth rates, operating margins, and discount rates. Changes in economic and operating conditions impacting these assumptions could result in goodwill impairment in future periods. The goodwill balance allocated to the Asset Lifecycle Management reporting unit was $579 million as of October 1, 2023 (goodwill impairment testing date). The fair value of the Asset Lifecycle Management reporting unit exceeded its carrying value as of the measurement date and, therefore, no impairment was recognized.

We identified the evaluation of goodwill for the Asset Lifecycle Management reporting unit for impairment as a critical audit matter because of the significant judgments made by management to estimate the fair value of the Asset Lifecycle Management reporting unit. Performing audit procedures to evaluate the reasonableness of management’s estimates and assumptions related to selection of the discount rate and forecasts of future revenue and operating margin of the Asset Lifecycle Management reporting unit required a high degree of auditor judgment and an increased extent of effort, including the need to involve our fair value specialists.

HOW THE CRITICAL AUDIT MATTER WAS ADDRESSED IN THE AUDIT

Our audit procedures related to testing the reasonableness of key assumptions within the Discounted Cash Flow Model of the Asset Lifecycle Management reporting unit. The key assumptions include future revenue growth rates, operating margins, and the selection of the discount rate. We performed the following procedures as part of the audit:

• We evaluated management’s ability to accurately forecast by comparing actual results to management’s historical forecasts.

• We evaluated the reasonableness of the revenue growth rates and operating margins presented within management’s Discounted Cash Flow Model by comparing it to (1) historical results, (2) internal communications to management and the Board of Directors, and (3) forecasted information included in Company press releases and industry reports in which Asset Lifecycle Management operates.

• With the assistance of our fair value specialists, we evaluated the discount rate, including testing the underlying source information and the mathematical accuracy of the calculation, and developing a range of independent estimates and comparing that to the discount rate selected by management.

• We tested the effectiveness of controls over the evaluation of goodwill for impairment, including those over the Discounted Cash Flow Model and discount rate.

/s/ DELOITTE & TOUCHE LLP

Boston, Massachusetts

February 22, 2024

We have served as the Company’s auditor since 2002.

			IRON MOUNTAIN 2023 FORM 10-K			67

Part IV

IRON MOUNTAIN INCORPORATED

CONSOLIDATED BALANCE SHEETS

(IN THOUSANDS, EXCEPT SHARE AND PER SHARE DATA)

			DECEMBER 31,
			2023						2022
ASSETS
Current Assets:
Cash and cash equivalents			$	222,789					$	141,797
Accounts receivable (less allowances of $74,762 and $54,143 as of December 31, 2023 and 2022, respectively)			1,259,826						1,174,915
Prepaid expenses and other			252,930						230,433
Total Current Assets			1,735,545						1,547,145
Property, plant and equipment			10,373,989						9,025,765
Less—Accumulated depreciation			(4,059,120)						(3,910,321)
Property, Plant and Equipment, net			6,314,869						5,115,444
Other Assets, Net:
Goodwill			5,017,912						4,882,734
Customer and supplier relationships and other intangible assets			1,279,800						1,423,145
Operating lease right-of-use assets			2,696,024						2,583,704
Other			429,652						588,342
Total Other Assets, Net			9,423,388						9,477,925
Total Assets			$	17,473,802					$	16,140,514
LIABILITIES AND EQUITY
Current Liabilities:
Current portion of long-term debt			$	120,670					$	87,546
Accounts payable			539,594						469,198
Accrued expenses and other current liabilities (includes current portion of operating lease liabilities)			1,250,259						1,031,910
Deferred revenue			325,665						328,910
Total Current Liabilities			2,236,188						1,917,564
Long-term Debt, net of current portion			11,812,500						10,481,449
Long-term Operating Lease Liabilities, net of current portion			2,562,394						2,429,167
Other Long-term Liabilities			237,590						317,376
Deferred Income Taxes			235,410						263,005
Commitments and Contingencies
Redeemable Noncontrolling Interests			177,947						95,160
Equity:
Iron Mountain Incorporated Stockholders’ Equity:
Preferred stock (par value $0.01; authorized 10,000,000 shares; none issued and outstanding)			—						—
Common stock (par value $0.01; authorized 400,000,000 shares; issued and outstanding 292,142,739 shares and 290,830,296 shares as of December 31, 2023 and 2022, respectively)			2,921						2,908
Additional paid-in capital			4,533,691						4,468,035
(Distributions in excess of earnings) earnings in excess of distributions			(3,953,808)						(3,392,272)
Accumulated other comprehensive items, net			(371,156)						(442,003)
Total Iron Mountain Incorporated Stockholders’ Equity			211,648						636,668
Noncontrolling Interests			125						125
Total Equity			211,773						636,793
Total Liabilities and Equity			$	17,473,802					$	16,140,514

The accompanying notes are an integral part of these consolidated financial statements.

68			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

CONSOLIDATED STATEMENTS OF OPERATIONS

(IN THOUSANDS, EXCEPT PER SHARE DATA)

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Revenues:
Storage rental			$	3,370,645					$	3,034,023					$	2,870,119
Service			2,109,644						2,069,551						1,621,412
Total Revenues			5,480,289						5,103,574						4,491,531
Operating Expenses:
Cost of sales (excluding depreciation and amortization)			2,357,800						2,189,120						1,887,229
Selling, general and administrative			1,236,287						1,140,577						1,022,559
Depreciation and amortization			776,159						727,595						680,422
Acquisition and Integration Costs			25,875						47,746						12,764
Restructuring and other transformation			175,215						41,933						206,426
(Gain) loss on disposal/write-down of property, plant and equipment, net			(12,825)						(93,268)						(172,041)
Total Operating Expenses			4,558,511						4,053,703						3,637,359
Operating Income (Loss)			921,778						1,049,871						854,172
Interest Expense, Net (includes Interest Income of $12,471, $8,276 and $7,341 in 2023, 2022 and 2021, respectively)			585,932						488,014						417,961
Other Expense (Income), Net			108,640						(69,781)						(192,804)
Net Income (Loss) Before Provision (Benefit) for Income Taxes			227,206						631,638						629,015
Provision (Benefit) for Income Taxes			39,943						69,489						176,290
Net Income (Loss)			187,263						562,149						452,725
Less: Net income (loss) attributable to noncontrolling interests			3,029						5,168						2,506
Net Income (Loss) Attributable to Iron Mountain Incorporated			$	184,234					$	556,981					$	450,219
Earnings (Losses) Per Share Attributable to Iron Mountain Incorporated:
Basic			$	0.63					$	1.92					$	1.56
Diluted			$	0.63					$	1.90					$	1.55
Weighted Average Common Shares Outstanding:
Basic			291,936						290,812						289,457
Diluted			293,965						292,444						290,975

The accompanying notes are an integral part of these consolidated financial statements.

			IRON MOUNTAIN 2023 FORM 10-K			69

Part IV

IRON MOUNTAIN INCORPORATED

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)

(IN THOUSANDS)

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Net Income (Loss)			$	187,263					$	562,149					$	452,725
Other Comprehensive Income (Loss):
Foreign Currency Translation Adjustment			80,657						(113,966)						(136,410)
Change in Fair Value of Derivative Instruments			(2,454)						9,829						52,380
Reclassifications from Accumulated Other Comprehensive Items, net			(7,580)						—						—
Total Other Comprehensive Income (Loss)			70,623						(104,137)						(84,030)
Comprehensive Income (Loss)			257,886						458,012						368,695
Comprehensive Income (Loss) Attributable to Noncontrolling Interests			2,805						4,687						930
Comprehensive Income (Loss) Attributable to Iron Mountain Incorporated			$	255,081					$	453,325					$	367,765

The accompanying notes are an integral part of these consolidated financial statements.

70			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

CONSOLIDATED STATEMENTS OF EQUITY

(IN THOUSANDS, EXCEPT SHARE DATA)

									IRON MOUNTAIN INCORPORATED STOCKHOLDERS’ EQUITY
									COMMON STOCK												ADDITIONAL PAID-IN CAPITAL						(DISTRIBUTIONS IN EXCESS OF EARNINGS) EARNINGS IN EXCESS OF DISTRIBUTIONS						ACCUMULATED OTHER COMPREHENSIVE ITEMS, NET						NONCONTROLLING INTERESTS									REDEEMABLE NONCONTROLLING INTERESTS
			TOTAL						SHARES						AMOUNTS
Balance, December 31, 2020			$	1,136,729					288,273,049						$	2,883					$	4,340,078					$	(2,950,339)					$	(255,893)					$	—								$	59,805
Issuance of shares under employee stock purchase plan and option plans and stock-based compensation			84,004						1,484,012						15						83,989						—						—						—									—
Changes in equity related to redeemable noncontrolling interests			(11,514)						—						—						(11,514)						—						—						—									11,682
Parent cash dividends declared			(721,032)						—						—						—						(721,032)						—						—									—
Other comprehensive (loss) income			(82,785)						—						—						—						—						(82,454)						(331)									(1,245)
Net income (loss)			450,355						—						—						—						450,219						—						136									2,370
Noncontrolling interests equity contributions			—						—						—						—						—						—						—									2,200
Noncontrolling interests dividends			—						—						—						—						—						—						—									(2,450)
Purchase of noncontrolling interests			1,311						—						—						—						—						—						1,311									2,567
Redemption of noncontrolling Interests			—						—						—						—						—						—						—									(2,518)
Balance, December 31, 2021			857,068						289,757,061						2,898						4,412,553						(3,221,152)						(338,347)						1,116									72,411
Issuance and net settlement of shares under employee stock purchase plan and option plans and stock-based compensation			52,012						1,073,235						10						52,002						—						—						—									—
Changes in equity related to noncontrolling interests			9,734						—						—						6,099						—						—						3,635									(8,264)
Parent cash dividends declared			(728,101)						—						—						—						(728,101)						—						—									—
Other comprehensive (loss) income			(104,250)						—						—						—						—						(103,656)						(594)									113
Net income (loss)			557,343						—						—						—						556,981						—						362									4,806
Noncontrolling interests equity contributions and related costs			(2,494)						—						—						(2,619)						—						—						125									29,047
Noncontrolling interests dividends			—						—						—						—						—						—						—									(2,953)
Redemption of noncontrolling Interests			(4,519)						—						—						—						—						—						(4,519)									—
Balance, December 31, 2022			636,793						290,830,296						2,908						4,468,035						(3,392,272)						(442,003)						125									95,160
Issuance and net settlement of shares under employee stock purchase plan and option plans and stock-based compensation			65,045						1,312,443						13						65,032						—						—						—									—
Changes in equity related to redeemable noncontrolling interests			970						—						—						970						—						—						—									(1,367)
Parent cash dividends declared			(745,770)						—						—						—						(745,770)						—						—									—
Other comprehensive income (loss)			70,847						—						—						—						—						70,847						—									(224)
Net income (loss)			184,234						—						—						—						184,234						—						—									3,029
Noncontrolling interests equity contributions and related costs			(346)						—						—						(346)						—						—						—									24,684
Noncontrolling interests dividends			—						—						—						—						—						—						—									(3,855)
Redemption and purchase of noncontrolling interests			—						—						—						—						—						—						—									60,520
Balance, December 31, 2023			$	211,773					292,142,739						$	2,921					$	4,533,691					$	(3,953,808)					$	(371,156)					$	125								$	177,947

The accompanying notes are an integral part of these consolidated financial statements.

			IRON MOUNTAIN 2023 FORM 10-K			71

Part IV

IRON MOUNTAIN INCORPORATED

CONSOLIDATED STATEMENTS OF CASH FLOWS

(IN THOUSANDS)

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Cash Flows from Operating Activities:
Net income (loss)			$	187,263					$	562,149					$	452,725
Adjustments to reconcile net income (loss) to cash flows from operating activities:
Depreciation			525,850						478,984						465,072
Amortization (includes amortization of deferred financing costs and discounts of $16,859, $18,044 and $16,548 in 2023, 2022 and 2021, respectively)			267,168						266,655						231,898
Revenue reduction associated with amortization of customer inducements and data center above- and below-market leases			7,036						8,119						8,852
Stock-based compensation expense			73,799						56,861						61,001
(Benefit) provision for deferred income taxes			(35,264)						(55,920)						28,703
(Gain) loss on disposal/write-down of property, plant and equipment, net			(12,825)						(93,268)						(172,041)
Loss (gain) on divestments and deconsolidations			—						105,825						(178,983)
Gain associated with the remeasurement of the Deferred Purchase Obligation			—						(93,600)						—
Loss (gain) associated with the Clutter transactions			38,000						(35,821)						—
Foreign currency transactions and other, net			103,134						(19,853)						(6,656)
(Increase) decrease in assets			(70,287)						(224,641)						(174,206)
Increase (decrease) in liabilities			29,693						(27,795)						42,537
Cash Flows from Operating Activities			1,113,567						927,695						758,902
Cash Flows from Investing Activities:
Capital expenditures			(1,339,223)						(875,378)						(611,082)
Cash paid for acquisitions, net of cash acquired			(41,849)						(803,690)						(203,998)
Acquisition of customer relationships			—						(2,143)						(5,892)
Customer inducements			(5,874)						(6,062)						(7,402)
Contract costs			(95,124)						(70,336)						(58,524)
Net proceeds from IPM Divestment			—						—						213,878
Investments in joint ventures and other investments			(15,830)						(73,233)						(78,623)
Proceeds from sales of property and equipment and other, net			53,544						170,419						278,330
Cash Flows from Investing Activities			(1,444,356)						(1,660,423)						(473,313)
Cash Flows from Financing Activities:
Repayment of revolving credit facility, term loan facilities and other debt			(18,191,921)						(11,593,452)						(5,164,483)
Proceeds from revolving credit facility, term loan facilities and other debt			18,386,168						12,949,766						4,972,214
Net proceeds from sales of senior notes			990,000						—						737,812
Debt financing and equity contribution from noncontrolling interests			24,684						29,172						—
Debt repayment and equity distribution to noncontrolling interests			(3,855)						(2,953)						(2,450)
Repurchase of noncontrolling interest			(400)						(4,519)						(75,000)
Parent cash dividends			(737,650)						(724,388)						(718,340)
Net (payments) proceeds associated with employee stock-based awards			(8,754)						(4,849)						25,860
Other, net			(32,606)						(9,570)						3,581
Cash Flows from Financing Activities			425,666						639,207						(220,806)
Effect of Exchange Rates on Cash and Cash Equivalents			(13,885)						(20,510)						(14,018)
Increase (decrease) in Cash and Cash Equivalents			80,992						(114,031)						50,765
Cash and Cash Equivalents, Beginning of Year			141,797						255,828						205,063
Cash and Cash Equivalents, End of Year			$	222,789					$	141,797					$	255,828
Supplemental Information:
Cash Paid for Interest			$	512,446					$	482,673					$	428,111
Cash Paid for Income Taxes, Net			$	89,599					$	99,631					$	130,292
Non-Cash Investing and Financing Activities:
Financing Leases and Other			$	135,492					$	49,836					$	50,552
Accrued Capital Expenditures			$	234,315					$	172,589					$	88,210
Deferred Purchase Obligations and Other Deferred Payments			$	18,575					$	193,033					$	—
Dividends Payable			$	202,392					$	194,272					$	190,559

The accompanying notes are an integral part of these consolidated financial statements.

72			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

DECEMBER 31, 2023

(In thousands, except share and per share data)

1. NATURE OF BUSINESS

The accompanying financial statements represent the consolidated accounts of Iron Mountain Incorporated, a Delaware corporation ("IMI"), and its subsidiaries ("we" or "us").

We help organizations around the world protect their information, reduce storage costs, comply with regulations, facilitate corporate disaster recovery and better use their information and information technology ("IT") infrastructure for business advantages, regardless of its format, location or life cycle stage. We do this by storing physical records and data backup media, offering information management solutions and providing data center space for enterprise-class colocation and hyperscale deployments. We offer comprehensive records and information management services and data management services, along with the expertise and experience to address complex storage and information management challenges such as rising storage rental costs, legal and regulatory compliance and disaster recovery requirements. We provide secure and reliable data center facilities to protect digital information and ensure the continued operation of our customers’ IT infrastructure, with reliable and flexible deployment options. Our asset lifecycle management ("ALM") business allows us to provide end-to-end asset lifecycle services for hyperscale, corporate data center and corporate end-user device assets.

In September 2022, we announced a global program designed to accelerate the growth of our business ("Project Matterhorn"). See Note 13.

We have been organized and have operated as a real estate investment trust for United States federal income tax purposes ("REIT") beginning with our taxable year ended December 31, 2014.

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

A. PRINCIPLES OF CONSOLIDATION

The accompanying financial statements reflect our financial position, results of operations, comprehensive income (loss), equity and cash flows on a consolidated basis. The accompanying financial statements include the results of those entities over which we have a controlling financial interest and we are deemed to be the primary beneficiary. All intercompany transactions and account balances have been eliminated.

B. USE OF ESTIMATES

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires us to make estimates, judgments and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and the related disclosure of contingent assets and liabilities at the date of the financial statements and for the period then ended. On an ongoing basis, we evaluate the estimates used. We base our estimates on historical experience, actuarial estimates, current conditions and various other assumptions that we believe to be reasonable under the circumstances. These estimates form the basis for making judgments about the carrying values of assets and liabilities and are not readily apparent from other sources. Actual results may differ from these estimates.

C. CHANGES IN PRESENTATION

Certain items previously reported under specific financial statement captions have been reclassified to conform to the current year presentation.

D. FOREIGN CURRENCY

Local currencies are the functional currencies for our operations outside the United States, with the exception of certain foreign holding companies, whose functional currency is the United States dollar. In those instances where the local currency is the functional currency, assets and liabilities are translated at period-end exchange rates, and revenues and expenses are translated at average exchange rates for the applicable period. See Note 2.r.

			IRON MOUNTAIN 2023 FORM 10-K			73

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

E. CASH AND CASH EQUIVALENTS

Cash and cash equivalents include cash on hand and cash invested in highly liquid short-term securities, which have remaining maturities at the date of purchase of less than 90 days. Cash and cash equivalents are carried at cost, which approximates fair value.

F. ALLOWANCE FOR DOUBTFUL ACCOUNTS AND CREDIT MEMO RESERVES

We maintain an allowance for doubtful accounts and a credit memo reserve for estimated losses resulting from the potential inability of our customers to make required payments and potential disputes regarding billing and service issues. We evaluate and monitor the collectability of accounts receivable based on a combination of factors, including historical loss experience, assessments of trends in our aged receivables and credit memo activity, the location of our businesses, the composition of our customer base, our product and service lines, potential future macroeconomic factors, including natural disasters, and reasonable and supportable forecasts for expected future collectability of our outstanding receivables. Continued adjustments will be made, as it becomes evident, should there be any material change to reasonable and supportable forecasts that may impact our likelihood of collection. Our highly diverse global customer base, with no single customer accounting for more than approximately 1% of revenue during the years ended December 31, 2023, 2022 and 2021, limits our exposure to concentration of credit risk. Additionally, we write off uncollectible balances as circumstances warrant, generally no later than one year past due.

The rollforward of the allowance for doubtful accounts and credit memo reserves is as follows:

YEAR ENDED DECEMBER 31,						BALANCE AT BEGINNING OF THE YEAR						CREDIT MEMOS CHARGED TO REVENUE						ALLOWANCE FOR BAD DEBTS CHARGED TO EXPENSE						DEDUCTIONS AND OTHER**(1)**						BALANCE AT END OF THE YEAR
2023						$	54,143					$	92,881					$	32,692					$	(104,954)					$	74,762
2022						62,009						62,891						13,666						(84,423)						54,143
2021						56,981						47,931						26,896						(69,799)						62,009

(1)Primarily consists of the issuance of credit memos, the write-off of accounts receivable and the impact associated with currency translation adjustments.

G. CONCENTRATIONS OF CREDIT RISK

Financial instruments that potentially subject us to credit risk consist principally of cash and cash equivalents (including money market funds and time deposits) and accounts receivable. The only significant concentrations of liquid investments as of December 31, 2023 and 2022 related to investments in money market funds. As per our risk management investment policy, we limit exposure to concentration of credit risk by limiting the amount invested in any one mutual fund to a maximum of 1% of the fund's total assets or in any one financial institution to a maximum of $75,000. See Note 2.p.

74			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

H. PREPAID EXPENSES AND ACCRUED EXPENSES

Prepaid expenses totaled $126,904 and $114,130 as of December 31, 2023 and 2022, respectively. There were no other items greater than 5% of total current assets included within Prepaid expenses and other as of December 31, 2023 and 2022.

Accrued expenses and other current liabilities with items greater than 5% of total current liabilities are shown separately and consist of the following:

						DECEMBER 31,
DESCRIPTION						2023						2022
Interest						$	175,218					$	128,272
Deferred purchase obligations, purchase price holdbacks and other						171,273						7,187
Dividends						202,392						194,272
Operating lease liabilities						291,795						288,738
Other						409,581						413,441
Accrued expenses and other current liabilities						$	1,250,259					$	1,031,910

I. PROPERTY, PLANT AND EQUIPMENT

Property, plant and equipment are stated at cost and depreciated using the straight-line method with the following useful lives (in years):

DESCRIPTION			RANGE
Buildings and building improvements			5 to 40
Leasehold improvements			5 to 10 or life of the lease (whichever is shorter)
Racking			1 to 20 or life of the lease (whichever is shorter)
Warehouse equipment/vehicles			1 to 10
Furniture and fixtures			1 to 10
Computer hardware and software			2 to 5

Property, plant and equipment (including financing leases in the respective categories), at cost, consist of the following:

						DECEMBER 31,
DESCRIPTION						2023						2022
Land						$	536,780					$	486,715
Buildings and building improvements						3,819,241						3,336,778
Leasehold improvements						1,166,810						1,079,419
Racking						2,054,046						2,058,054
Warehouse equipment/vehicles						526,965						493,128
Furniture and fixtures						46,094						49,610
Computer hardware and software						601,273						585,792
Construction in progress						1,622,780						936,269
Property, plant and equipment						$	10,373,989					$	9,025,765

Minor maintenance costs are expensed as incurred. Major improvements which extend the life, increase the capacity or improve the safety or the efficiency of property owned are capitalized and depreciated. Major improvements to leased buildings are capitalized as leasehold improvements and depreciated.

			IRON MOUNTAIN 2023 FORM 10-K			75

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

CAPITALIZED INTEREST

We capitalize interest expense during the active construction period of major capital projects. Capitalized interest is added to the cost of the underlying assets and is amortized over the useful lives of the assets. During the years ended December 31, 2023, 2022 and 2021, capitalized interest is as follows:

						YEAR ENDED DECEMBER 31,
						2023						2022						2021
Capitalized interest						$	44,845					$	14,078					$	12,673

INTERNAL USE SOFTWARE

We develop various software applications for internal use. Computer software costs associated with internal use software are expensed as incurred until certain capitalization criteria are met. Third party consulting costs, as well as payroll and related costs for employees directly associated with, and devoting time to, the development of internal use computer software projects (to the extent time is spent directly on the project) are capitalized. Capitalization of costs, including costs incurred for upgrades and enhancements that provide additional functionality to our existing software, generally begins during the application development stage of the project, which occurs after it is probable that the project will be completed and used to perform the function intended. Capitalization ends when the asset is ready for its intended use. Capitalized internal use software costs are depreciated on a straight-line basis over the expected useful life of the software, commencing when the software is ready for its intended use. Computer software costs that are capitalized are periodically evaluated for impairment.

During the years ended December 31, 2023, 2022 and 2021, capitalized costs associated with the development of internal use computer software projects are as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Capitalized costs associated with the development of internal use computer software projects			$	64,488					$	44,152					$	48,557

ASSET RETIREMENT OBLIGATIONS

Entities are required to record the fair value of a liability for an asset retirement obligation in the period in which it is incurred. Asset retirement obligations represent the costs to replace or remove tangible long-lived assets required by law, regulatory rule or contractual agreement. Our asset retirement obligations are primarily the result of requirements under our facility lease agreements which generally have "return to original condition" clauses which would require us to remove or restore items such as shred pits, vaults, demising walls and office build-outs, among others. The significant assumptions used in estimating our aggregate asset retirement obligations are the timing of removals, the probability of a requirement to perform, estimated cost and associated expected inflation rates that are consistent with historical rates and credit-adjusted risk-free rates that approximate our incremental borrowing rate. Our asset retirement obligations at December 31, 2023 and 2022 were $36,602 and $36,119, respectively, and are included in Other Long-term Liabilities in our Consolidated Balance Sheets.

76			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

J. LEASES

We lease facilities for certain warehouses, data centers and office space. We also have land leases, including those on which certain facilities are located. The majority of our leased facilities are classified as operating leases that, on average, have initial lease terms of five to 10 years, with one or more lease renewal options to extend the lease term. Our lease renewal option terms generally range from one to five years. The exercise of the lease renewal option is at our sole discretion and may contain fixed rent, fair market value based rent or Consumer Price Index rent escalation clauses. We include option periods in the lease term when our failure to renew the lease would result in an economic disincentive, thereby making it reasonably certain that we will renew the lease. We recognize straight line rental expense over the life of the lease and any fair market value or Consumer Price Index rent escalations are recognized as variable lease expense in the period in which the obligation is incurred. In addition, we lease certain vehicles and equipment. Vehicle and equipment leases typically have lease terms ranging from one to seven years.

We account for all leases, both operating and financing, in accordance with Accounting Standards Codification ("ASC") Topic 842, Leases ("ASC 842"). Our accounting policy provides that leases with an initial term of 12 months or less will not be included within the lease right-of-use assets and lease liabilities recognized on our Consolidated Balance Sheets. We recognize the lease payments for those leases with an initial term of 12 months or less in our Consolidated Statements of Operations on a straight-line basis over the lease term.

The lease right-of-use assets and related lease liabilities are classified as either operating or financing. Lease right-of-use assets are calculated as the net present value of future payments plus any capitalized initial direct costs less any tenant improvements or lease incentives. Lease liabilities are calculated as the net present value of future payments. In calculating the present value of the lease payments, we utilize the rate stated in the lease (in the limited circumstances when such rate is explicitly stated) or, if no rate is explicitly stated, we utilize a rate that reflects our securitized incremental borrowing rate by geography for the lease term. We account for nonlease components (which include common area maintenance, taxes, and insurance) with the related lease component. Any variable nonlease components are not included within the lease right-of-use asset and lease liability on our Consolidated Balance Sheets, and instead, are reflected as an expense in the period incurred.

Operating and financing lease right-of-use assets and lease liabilities as of December 31, 2023 and 2022 are as follows:

						DECEMBER 31,
DESCRIPTION						2023						2022
Assets:
Operating lease right-of-use assets(1)						$	2,696,024					$	2,583,704
Financing lease right-of-use assets, net of accumulated depreciation(2)(3)						304,600						251,690
Liabilities:
Current
Operating lease liabilities						$	291,795					$	288,738
Financing lease liabilities(3)						39,089						43,857
Long-term
Operating lease liabilities						$	2,562,394					$	2,429,167
Financing lease liabilities(3)						310,776						289,048

(1)At December 31, 2023 and 2022, these assets are comprised of approximately 99% real estate related assets (which include land, buildings and racking) and 1% non-real estate related assets (which include warehouse equipment, vehicles, furniture and fixtures and computer hardware and software).

(2)At December 31, 2023, these assets are comprised of approximately 68% real estate related assets and 32% non-real estate related assets. At December 31, 2022, these assets are comprised of approximately 64% real estate related assets and 36% non-real estate related assets.

(3)Financing lease right-of-use assets, current financing lease liabilities and long-term financing lease liabilities are included within Property, Plant and Equipment, Net, Current portion of long-term debt and Long-term Debt, net of current portion, respectively, within our Consolidated Balance Sheets.

			IRON MOUNTAIN 2023 FORM 10-K			77

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

The components of the lease expense for the years ended December 31, 2023, 2022 and 2021 are as follows:

						YEAR ENDED DECEMBER 31,
DESCRIPTION						2023						2022						2021
Operating lease cost(1)						$	660,889					$	574,115					$	545,097
Financing lease cost:
Depreciation of financing lease right-of-use assets						$	42,089					$	42,708					$	50,970
Interest expense for financing lease liabilities						18,638						17,329						19,808

(1)Operating lease cost, the majority of which is included in Cost of sales, includes variable lease costs of $142,154, $119,184 and $111,949 for the years ended December 31, 2023, 2022 and 2021, respectively.

Weighted average remaining lease terms and discount rates as of December 31, 2023 and 2022 are as follows:

			DECEMBER 31, 2023												DECEMBER 31, 2022
			OPERATING LEASES						FINANCING LEASES						OPERATING LEASES						FINANCING LEASES
Remaining Lease Term			10.6 years						9.2 years						11.3 years						10.6 years
Discount Rate			6.6		%				6.1		%				6.4		%				5.8		%

The estimated minimum future lease payments (receipts) as of December 31, 2023 are as follows:

YEAR						OPERATING LEASES**(1)**						SUBLEASE INCOME						FINANCING LEASES**(1)**
2024						$	468,015					$	(6,969)					$	56,901
2025						456,638						(4,282)						127,074
2026						421,535						(2,979)						40,283
2027						389,307						(3,451)						30,098
2028						344,744						(48)						55,523
Thereafter						1,970,950						(48)						117,779
Total minimum lease payments (receipts)						4,051,189						$	(17,777)					427,658
Less amounts representing interest or imputed interest						1,197,000												77,793
Present value of lease obligations						$	2,854,189											$	349,865

(1)Estimated minimum future lease payments exclude variable common area maintenance charges, insurance and taxes.

At December 31, 2023, we had four leases which we have signed but which have not yet commenced and are not included in our lease obligation table above. The total undiscounted minimum lease payments for these leases are approximately $239,146 and have lease terms that range from 14 to 25 years. Each of these leases is expected to commence during 2024.

78			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

Other information: Supplemental cash flow information relating to our leases for the years ended December 31, 2023, 2022 and 2021 is as follows:

						YEAR ENDED DECEMBER 31,
CASH PAID FOR AMOUNTS INCLUDED IN MEASUREMENT OF LEASE LIABILITIES:						2023						2022						2021
Operating cash flows used in operating leases						$	450,412					$	409,163					$	392,987
Operating cash flows used in financing leases (interest)						18,638						17,329						19,808
Financing cash flows used in financing leases						52,284						44,869						46,118
NON-CASH ITEMS:
Operating lease modifications and reassessments						$	86,948					$	179,094					$	144,310
New operating leases (including acquisitions and sale-leaseback transactions)						306,479						540,830						282,490

K. LONG-LIVED ASSETS

We review long-lived assets for impairment whenever events or changes in circumstances indicate the carrying amount of such assets may not be recoverable. Recoverability of these assets is determined by comparing the sum of the forecasted undiscounted net cash flows of the operation to which the assets relate to their carrying amount. The operations are generally distinguished by the business segment and geographic region in which they operate. If it is determined that we are unable to recover the carrying amount of the assets, the long-lived assets are written down, on a pro rata basis, to fair value. Fair value is determined based on discounted cash flows or appraised values, depending upon the nature of the assets. Long-lived assets, including finite-lived intangible assets, are amortized over their useful lives. Annually, or more frequently if events or circumstances warrant, we assess whether a change in the lives over which long-lived assets, including finite-lived intangible assets, are amortized is necessary.

			IRON MOUNTAIN 2023 FORM 10-K			79

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

Gain on disposal/write-down of property, plant and equipment, net for the years ended December 31, 2023, 2022 and 2021 is as follows:

			YEAR ENDED DECEMBER 31,
			2023			2022			2021
Gain on disposal/write-down of property, plant and equipment, net			$	12,825		$	93,268		$	172,041
The gains primarily consist of(1):			•Gains associated with sale and sale-leaseback transactions of approximately $19,500, of which approximately $18,500 relates to a sale-leaseback transaction of a facility in Singapore during the first quarter of 2023. These gains are partially offset by losses related to the disposal of assets associated with facility consolidations.			•Gains associated with sale and sale-leaseback transactions of approximately $94,500, of which (i) approximately $49,000 relates to sale and sale-leaseback transactions of 11 facilities and parcels of land in the United States during the second quarter of 2022, (ii) approximately $17,000 relates to sale-leaseback transactions of two facilities in the United States and one in Canada during the third quarter of 2022 and (iii) approximately $28,500 relates to sale and sale-leaseback transactions of 12 facilities and one parcel of land in the United States and one facility in the United Kingdom during the fourth quarter of 2022.			•Gains associated with sale and sale-leaseback transactions of approximately $164,000, of which (i) approximately $127,400 relates to sale-leaseback transactions of five facilities in the United Kingdom during the second quarter of 2021 and (ii) approximately $36,600 relates to sale and sale-leaseback transactions of nine facilities in the United States during the fourth quarter of 2021.

(1) The gains recognized during the years ended December 31, 2023, 2022 and 2021 are the result of our program to monetize a small portion of our industrial assets through sale and sale-leaseback transactions. The terms for these leases are consistent with the terms of our lease portfolio, which are disclosed in Note 2.j.

L. GOODWILL AND OTHER INDEFINITE-LIVED INTANGIBLE ASSETS

Goodwill and intangible assets with indefinite lives are not amortized but are reviewed annually for impairment, or more frequently if impairment indicators arise. Other than goodwill, we currently have no intangible assets that have indefinite lives and which are not amortized.

We test goodwill annually on October 1, and more frequently if impairment indicators arise that would require an interim test. We have performed our annual goodwill impairment review as of October 1, 2023, 2022 and 2021. We concluded that as of October 1, 2023, 2022 and 2021, goodwill was not impaired.

80			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

REPORTING UNITS AS OF OCTOBER 1, 2022

Our reporting units at which level we performed our goodwill impairment analysis as of October 1, 2022 were as follows:

•North America Records and Information Management ("North America RIM") •Europe and South Africa Records and Information Management ("ESA RIM") •Middle East, North Africa and Turkey Information Management ("MENAT RIM") •Latin America Records and Information Management ("Latin America RIM")			•Asia Pacific Records and Information Management ("APAC RIM") •Entertainment Services •Global Data Center •Fine Arts •ALM

There were no changes to the composition of our reporting units between October 1, 2022 and December 31, 2022.

GOODWILL BY REPORTING UNIT AS OF DECEMBER 31, 2022

The carrying value of goodwill, net for each of our reporting units described above as of December 31, 2022 is as follows:

SEGMENT			REPORTING UNIT			CARRYING VALUE AS OF DECEMBER 31, 2022
Global RIM Business			North America RIM			$	2,667,400
ESA RIM			521,949
MENAT RIM			25,007
Latin America RIM			109,069
APAC RIM			497,792
Entertainment Services			31,729
Global Data Center Business			Global Data Center			418,502
Corporate and Other			Fine Arts			33,908
			ALM			577,378
Total						$	4,882,734

			IRON MOUNTAIN 2023 FORM 10-K			81

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

2023 REPORTING UNIT CHANGES

During 2023, as a result of the realignment of our global managerial structure, we reassessed the composition of our reporting units. The realignment of our global managerial structure did not change the composition of our reportable segments (as described and defined in Note 11). The reassessment resulted in the following changes to our reporting units: (i) our South Africa business, which was previously managed with our other businesses in Europe as part of our former ESA RIM reporting unit, is now managed as part of our former MENAT RIM reporting unit and these will comprise our "MENATSA RIM" reporting unit and (ii) our other businesses in Europe are now managed as our "Europe RIM" reporting unit.

There were no changes to our other reporting units. We have reassigned goodwill associated with the reporting units impacted by the realignment on a relative fair value basis, where appropriate. The fair value of each of our new reporting units was determined based on the application of a combined weighted average approach of preliminary fair value multiples of revenue and earnings and discounted cash flow techniques. These fair values represent our best estimate and preliminary assessment of goodwill allocations to each of the new reporting units on a relative fair value basis. We have completed an interim goodwill impairment analysis before and after the reporting unit changes, and we have concluded that the goodwill associated with each of our reporting units was not impaired.

REPORTING UNITS AS OF OCTOBER 1, 2023

Our reporting units at which level we performed our goodwill impairment analysis as of October 1, 2023 were as follows:

•North America RIM •Europe RIM •MENATSA RIM •Latin America RIM •APAC RIM			•Entertainment Services •Global Data Center •Fine Arts •ALM

There were no changes to the composition of our reporting units between October 1, 2023 and December 31, 2023.

GOODWILL BY REPORTING UNIT AS OF DECEMBER 31, 2023

The carrying value of goodwill, net for each of our reporting units described above as of December 31, 2023 is as follows:

SEGMENT			REPORTING UNIT			CARRYING VALUE AS OF DECEMBER 31, 2023
Global RIM Business			North America RIM			$	2,694,093
Europe RIM			541,860
MENATSA RIM			26,502
Latin America RIM			120,119
APAC RIM			496,944
Entertainment Services			32,427
Global Data Center Business			Global Data Center			478,930
Corporate and Other			Fine Arts			47,535
			ALM			579,502
Total						$	5,017,912

82			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

The fair value of our reporting units has generally been determined using a combined approach based on the present value of future cash flows (the "Discounted Cash Flow Model") and market multiples (the "Market Approach").

The Discounted Cash Flow Model incorporates significant assumptions including future revenue growth rates, operating margins, discount rates and capital expenditures.			The Market Approach requires us to make assumptions related to Adjusted EBITDA (as defined in Note 11) multiples.

Changes in economic and operating conditions impacting these assumptions or changes in multiples could result in goodwill impairments in future periods. In conjunction with our annual goodwill impairment reviews, we reconcile the sum of the valuations of all of our reporting units to our market capitalization as of such dates.

The changes in the carrying value of goodwill attributable to each reportable segment for the years ended December 31, 2023 and 2022 are as follows:

			GLOBAL RIM BUSINESS						GLOBAL DATA CENTER BUSINESS						CORPORATE AND OTHER						TOTAL CONSOLIDATED
Goodwill balance, net of accumulated amortization, as of December 31, 2021			$	3,972,852					$	426,074					$	64,605					$	4,463,531
Tax deductible goodwill acquired during the year			—						—						912						912
Non-tax deductible goodwill acquired during the year			696						—						546,693						547,389
Fair value and other adjustments(1)			(12,199)						—						384						(11,815)
Currency effects			(108,403)						(7,572)						(1,308)						(117,283)
Goodwill balance, net of accumulated amortization, as of December 31, 2022			3,852,946						418,502						611,286						4,882,734
Tax deductible goodwill acquired during the year			—						—						11,928						11,928
Non-tax deductible goodwill acquired during the year			21,594						56,674						383						78,651
Fair value and other adjustments			(80)						—						2,333						2,253
Currency effects			37,485						3,754						1,107						42,346
Goodwill balance, net of accumulated amortization, as of December 31, 2023			$	3,911,945					$	478,930					$	627,037					$	5,017,912
Accumulated Goodwill Impairment Balance as of December 31, 2022			$	132,409					$	—					$	26,011					$	158,420
Accumulated Goodwill Impairment Balance as of December 31, 2023			$	132,409					$	—					$	26,011					$	158,420

(1) This amount primarily represents an adjustment to goodwill as a result of the deconsolidation of certain businesses, as described in Note 4.

M. FINITE-LIVED INTANGIBLE ASSETS AND LIABILITIES

I. CUSTOMER AND SUPPLIER RELATIONSHIP INTANGIBLE ASSETS

Customer and supplier relationship intangible assets, which are acquired through either business combinations or acquisitions of customer relationships, are generally amortized over periods ranging from 10 to 30 years. Customer and supplier relationship intangible assets are recorded based upon estimates of their fair value.

			IRON MOUNTAIN 2023 FORM 10-K			83

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

II. CUSTOMER INDUCEMENTS

Payments that are made to a customer in order to terminate the customer’s storage of records with its current records management vendor ("Permanent Withdrawal Fees"), or direct payments to a customer for which no distinct benefit is received in return, are collectively referred to as "Customer Inducements". Customer Inducements are treated as a reduction of the transaction price over the associated contract terms, which range from one to 10 years, and are included in storage and service revenue in the accompanying Consolidated Statements of Operations. If the customer terminates its relationship with us, the unamortized carrying value of the Customer Inducement intangible asset is charged to revenue. However, in the event of such termination, we generally collect, and record as revenue, Permanent Withdrawal Fees that generally equal or exceed the amount of the unamortized Customer Inducement intangible asset.

III. DATA CENTER INTANGIBLE ASSETS AND LIABILITIES

Finite-lived intangible assets associated with our Global Data Center Business consist of the following:

DATA CENTER IN-PLACE LEASE INTANGIBLE ASSETS AND DATA CENTER TENANT RELATIONSHIP INTANGIBLE ASSETS

Data center in-place lease intangible assets ("Data Center In-Place Leases") and data center tenant relationship intangible assets ("Data Center Tenant Relationships") reflect the value associated with acquiring a data center operation with active tenants as of the date of acquisition. The value of Data Center In-Place Leases is determined based upon an estimate of the economic costs (such as lost revenues, tenant improvement costs, commissions, legal expenses and other costs to acquire new data center leases) avoided by acquiring a data center operation with active tenants. Data Center In-Place Leases are amortized over the weighted average remaining term of the acquired data center leases. The value of Data Center Tenant Relationships is determined based upon an estimate of the economic costs avoided upon lease renewal of the acquired tenants, based upon expectations of lease renewal. Data Center Tenant Relationships are amortized over the weighted average remaining anticipated life of the relationship with the acquired tenant.

DATA CENTER ABOVE-MARKET AND BELOW-MARKET IN-PLACE LEASE INTANGIBLE ASSETS

Data center above-market in-place lease intangible assets ("Data Center Above-Market Leases") and data center below-market in-place lease intangible assets ("Data Center Below-Market Leases") are recorded at the net present value of the difference between (i) the contractual amounts to be paid pursuant to each in-place lease and (ii) management’s estimate of the fair market lease rates for each corresponding in-place lease. Data Center Above-Market Leases and Data Center Below-Market Leases are amortized over the remaining non-cancellable term of the acquired in-place lease to storage revenue.

84			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

The gross carrying amount and accumulated amortization of our finite-lived intangible assets as of December 31, 2023 and 2022, respectively, are as follows:

			DECEMBER 31, 2023												DECEMBER 31, 2022
DESCRIPTION			GROSS CARRYING AMOUNT			ACCUMULATED AMORTIZATION			NET CARRYING AMOUNT						GROSS CARRYING AMOUNT			ACCUMULATED AMORTIZATION			NET CARRYING AMOUNT
Assets:
Customer and supplier relationship intangible assets(1)			$	2,144,641		$	(933,084)		$	1,211,557					$	2,162,154		$	(823,392)		$	1,338,762
Customer inducements(1)			47,565			(25,562)			22,003						47,794			(26,158)			21,636
Data center lease-based intangible assets(1)(2)			141,628			(95,422)			46,206						272,649			(209,902)			62,747
Third-party commissions asset and other(3)			77,638			(39,323)			38,315						83,297			(28,581)			54,716
Liabilities:
Data center below-market leases(4)			$	10,873		$	(5,772)		$	5,101					$	12,831		$	(7,806)		$	5,025

(1)Included in Customer and supplier relationship and other intangible assets in the accompanying Consolidated Balance Sheets.

(2)Data center lease-based intangible assets includes Data Center In-Place Leases, Data Center Tenant Relationships and Data Center Above-Market Leases.

(3)Included in Other (within Other Assets, Net) in the accompanying Consolidated Balance Sheets.

(4)Included in Other long-term liabilities in the accompanying Consolidated Balance Sheets.

Amortization expense associated with finite-lived intangible assets, revenue reduction associated with the amortization of Customer Inducements and net revenue reduction associated with the amortization of Data Center Above-Market Leases and Data Center Below-Market Leases for the years ended December 31, 2023, 2022 and 2021 is as follows:

						YEAR ENDED DECEMBER 31,
						2023						2022						2021
Amortization expense included in depreciation and amortization associated with:
Customer and supplier relationship intangible assets						$	153,128					$	156,779					$	117,761
Data center in-place leases and tenant relationships						22,322						16,955						42,333
Third-party commissions asset and other						12,541						16,148						6,987
Revenue reduction associated with amortization of:
Customer inducements and data center above-market and below-market leases						$	7,036					$	8,119					$	8,852

Estimated amortization expense for existing finite-lived intangible assets (excluding Contract Costs, as defined and disclosed in Note 2.s.) is as follows:

						ESTIMATED AMORTIZATION
YEAR						INCLUDED IN DEPRECIATION AND AMORTIZATION						REVENUE REDUCTION ASSOCIATED WITH CUSTOMER INDUCEMENTS AND DATA CENTER ABOVE-MARKET AND BELOW-MARKET LEASES
2024						$	187,933					$	5,982
2025						173,432						3,494
2026						156,946						2,607
2027						127,284						2,096
2028						116,387						1,729
Thereafter						533,747						1,343

			IRON MOUNTAIN 2023 FORM 10-K			85

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

N. DEFERRED FINANCING COSTS

Deferred financing costs are amortized over the life of the related debt. If debt is retired early, the related unamortized deferred financing costs are written off in the period the debt is retired and included as a component of Other expense (income), net. See Note 7.

O. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES

Derivative instruments are measured at fair value and are recorded as either assets or liabilities in our Consolidated Balance Sheets. Periodically, we acquire derivative instruments that are intended to hedge either cash flows or values that are subject to foreign exchange or other market price risk and not for trading purposes. We have formally documented our hedging relationships, including identification of the hedging instruments and the hedged items, as well as our risk management objectives and strategies for undertaking each hedge transaction. Given the recurring nature of our revenues and the long-term nature of our asset base, we have the ability and the preference to use long-term, fixed interest rate debt to finance our business, thereby preserving our long-term returns on invested capital. We may use interest rate swaps as a tool to maintain our targeted level of fixed rate debt. In addition, we may enter into cross-currency swaps to hedge the variability of exchange rates between the United States dollar and the currencies of our foreign subsidiaries, as well as interest rates. We may also use borrowings in foreign currencies, either obtained in the United States or by our foreign subsidiaries, to hedge foreign currency risk associated with our international investments. Gains and losses realized as a result of the maturing or termination of our interest rate swaps and cross-currency swaps are reflected as operating cash flows within our Consolidated Statements of Cash Flows. As of December 31, 2023 and 2022, none of our derivative instruments contained credit-risk related contingent features. See Note 6.

P. FAIR VALUE MEASUREMENTS

Entities are permitted under GAAP to elect to measure certain financial instruments and certain other items at either fair value or cost. We have elected the cost measurement option in all circumstances where we had an option.

Our financial assets or liabilities that are carried at fair value are required to be measured using inputs from the three levels of the fair value hierarchy. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The three levels of the fair value hierarchy are as follows:

Level 1—Inputs are unadjusted quoted prices in active markets for identical assets or liabilities that we have the ability to access at the measurement date.

Level 2—Inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable for the asset or liability (i.e., interest rates, yield curves, etc.), and inputs that are derived principally from or corroborated by observable market data by correlation or other means (market corroborated inputs).

Level 3—Unobservable inputs that reflect our assumptions about the assumptions that market participants would use in pricing the asset or liability.

86			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

The assets and liabilities carried at fair value and measured on a recurring basis as of December 31, 2023 and 2022, respectively, are as follows:

												FAIR VALUE MEASUREMENTS AT DECEMBER 31, 2023 USING
DESCRIPTION						TOTAL CARRYING VALUE AT DECEMBER 31, 2023						QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1)						SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)						SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Money Market Funds(1)						$	66,008					$	—					$	66,008					$	—
Time Deposits(1)						15,913						—						15,913						—
Trading Securities						9,952						6,149			(2)			3,803			(3)			—
Derivative Assets(4)						6,359						—						6,359						—
Derivative Liabilities(4)						5,769						—						5,769						—
Deferred Purchase Obligations(5)						208,265						—						—						208,265

												FAIR VALUE MEASUREMENTS AT DECEMBER 31, 2022 USING
DESCRIPTION						TOTAL CARRYING VALUE AT DECEMBER 31, 2022						QUOTED PRICES IN ACTIVE MARKETS (LEVEL 1)						SIGNIFICANT OTHER OBSERVABLE INPUTS (LEVEL 2)						SIGNIFICANT UNOBSERVABLE INPUTS (LEVEL 3)
Money Market Funds(1)						$	11,311					$	—					$	11,311					$	—
Time Deposits(1)						1,102						—						1,102						—
Trading Securities						9,462						9,426			(2)			36			(3)			—
Derivative Assets(4)						51,396						—						51,396						—
Derivative Liabilities(4)						489						—						489						—
Deferred Purchase Obligations(5)						193,033						—						—						193,033

(1)Money market funds and time deposits are measured based on quoted prices for similar assets and/or subsequent transactions.

(2)Certain trading securities are measured at fair value using quoted market prices.

(3)Certain trading securities are measured based on inputs other than quoted market prices that are observable.

(4)Derivative assets and liabilities include (i) interest rate swap agreements, and (ii) cross-currency swap agreements to hedge the variability of exchange rate impacts between the United States dollar and the Euro and certain of our Euro denominated subsidiaries. Our derivative financial instruments are measured using industry standard valuation models using market-based observable inputs, including interest rate curves, forward and spot prices for currencies and implied volatilities. Credit risk is also factored into the determination of the fair value of our derivative financial instruments. See Note 6 for additional information on our derivative financial instruments.

(5)Primarily relates to the fair value of the Deferred Purchase Obligation associated with the ITRenew Transaction (each as defined in Note 3), which was determined utilizing a Monte Carlo model and takes into account our forecasted projections as it relates to the underlying performance of the business. The Monte Carlo simulation model incorporates assumptions as to expected gross profits over the applicable achievement period, including adjustments for the volatility of timing and amount of the associated revenue and costs, as well as discount rates that account for the risk of the underlying arrangement and overall market risks. Any material change to these assumptions may result in a significantly higher or lower fair value of the Deferred Purchase Obligation. During the fourth quarter of 2022, we recorded a change in the estimated fair value of the Deferred Purchase Obligation as described in Note 2.v. The change in value of the Deferred Purchase Obligation during the year ended December 31, 2023 was driven by the accretion of the obligation to present value.

There were no material items that were measured at fair value on a non-recurring basis for the years ended December 31, 2023 and 2022 other than (i) the reporting units as presented in our goodwill impairment analysis (as disclosed in Note 2.l.); (ii) assets acquired and liabilities assumed through our acquisitions (as disclosed in Note 3); (iii) the redemption value of recently acquired noncontrolling interests and previously held equity interests (both as disclosed in Note 3); (iv) contributions to our equity method investments; and (v) the fair value of our retained investment of our deconsolidated businesses (as described in Note 4), all of which are based on Level 3 inputs.

The fair value of our long-term debt, which was determined based on Level 2 and Level 3 inputs, is disclosed in Note 7. Long-term debt is measured at cost in our Consolidated Balance Sheets as of December 31, 2023 and 2022.

			IRON MOUNTAIN 2023 FORM 10-K			87

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

Q. REDEEMABLE NONCONTROLLING INTERESTS

Certain unaffiliated third parties own noncontrolling interests in certain of our consolidated subsidiaries. The underlying agreements between us and our noncontrolling interest shareholders for these subsidiaries contain provisions under which the noncontrolling interest shareholders can require us to purchase their respective interests in such subsidiaries at certain times and at a purchase price as stipulated in the underlying agreements (generally at fair value). These put options make these noncontrolling interests redeemable and, therefore, these noncontrolling interests are classified as temporary equity outside of stockholders’ equity. Redeemable noncontrolling interests are reported at the higher of their redemption value or the noncontrolling interest holders’ proportionate share of the underlying subsidiaries net carrying value. Increases or decreases in the redemption value of the noncontrolling interest are offset against Additional Paid-in Capital.

When our noncontrolling interests become mandatorily redeemable, they are included as a component of either Accrued expenses and other current liabilities or Other long-term liabilities on our Consolidated Balance Sheets, depending on the timing of the redemption.

R. ACCUMULATED OTHER COMPREHENSIVE ITEMS, NET

The changes in Accumulated other comprehensive items, net for the years ended December 31, 2023, 2022 and 2021 are as follows:

			FOREIGN CURRENCY TRANSLATION AND OTHER ADJUSTMENTS						CHANGE IN FAIR VALUE OF DERIVATIVE INSTRUMENTS						TOTAL
Balance as of December 31, 2020			$	(206,190)					$	(49,703)					$	(255,893)
Other comprehensive (loss) income:
Foreign currency translation and other adjustments			(134,834)						—						(134,834)
Change in fair value of derivative instruments			—						52,380						52,380
Total other comprehensive (loss) income			(134,834)						52,380						(82,454)
Balance as of December 31, 2021			(341,024)						2,677						(338,347)
Other comprehensive (loss) income:
Foreign currency translation and other adjustments			(113,485)						—						(113,485)
Change in fair value of derivative instruments			—						9,829						9,829
Total other comprehensive (loss) income			(113,485)						9,829						(103,656)
Balance as of December 31, 2022			(454,509)						12,506						(442,003)
Other comprehensive income (loss):
Foreign currency translation and other adjustments			80,881						—						80,881
Change in fair value of derivative instruments			—						(2,454)						(2,454)
Reclassifications from Accumulated Other Comprehensive Items, net			—						(7,580)						(7,580)
Total other comprehensive income (loss)			80,881						(10,034)						70,847
Balance as of December 31, 2023			$	(373,628)					$	2,472					$	(371,156)

88			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

S. REVENUES

Our revenues consist of storage rental revenues as well as service revenues and are reflected net of sales and value-added taxes. Storage rental revenues, which are considered a key driver of financial performance for the storage and information management services industry, consist primarily of recurring periodic rental charges related to the storage of materials or data (generally on a per unit basis) that are typically retained by customers for many years and of revenues associated with our data center operations. Service revenues include charges for related service activities, the most significant of which include: (1) the handling of records, including the addition of new records, temporary removal of records from storage, refiling of removed records, customer termination and permanent withdrawal fees, project revenues and courier operations consisting primarily of the pickup and delivery of records upon customer request; (2) destruction services, consisting primarily of (i) secure shredding of sensitive documents and the subsequent sale of shredded paper for recycling, the price of which can fluctuate from period to period, and (ii) the decommissioning, data erasure, processing and disposition or sale of IT hardware and component assets; (3) digital solutions, including the scanning, imaging and document conversion services of active and inactive records, and consulting services; and (4) data center services, including set up, monitoring and support of our customers' assets which are protected in our data center facilities, and special project services, including data center fitout.

We account for our revenue in accordance with ASC 606, Revenue from Contracts with Customers ("ASC 606"), with the exception of our data center revenue, as described below. Customers are generally billed monthly based on contractually agreed-upon terms, and storage rental and service revenues are recognized in the month the respective storage rental or service is provided, in line with the transfer of control to the customer. When storage rental fees or services are billed in advance, amounts related to future storage rental or prepaid service contracts are accounted for as deferred revenue and recognized upon the transfer of control to the customer, generally ratably over the contract term. Customer contracts generally include promises to provide monthly recurring storage and related services that are essentially the same over time and have the same pattern of transfer of control to the customer; therefore, most performance obligations represent a promise to deliver a series of distinct services over time (as determined for purposes of ASC 606, a "series"). For those contracts that qualify as a series, we apply the "right to invoice" practical expedient as we have a right to consideration from the customer in an amount that corresponds directly with the value of the underlying performance obligation transferred to the customer to date. Additionally, each purchasing decision is fully in the control of the customer; therefore, consideration beyond the current reporting period is variable and allocated to the specific period to which the consideration relates, which is consistent with the practical expedient. Revenue from product sales, the significant majority of which are shred paper and IT asset sales, is recognized at the point in time at which control transfers to the customer, which is generally upon shipment.

Our Global Data Center Business features storage rental provided to the customer at contractually specified rates over a fixed contractual period. The revenue related to the storage component of our Global Data Center Business is recognized on a straight-line basis over the contract term in accordance with ASC 842. The revenue related to the service component of our Global Data Center Business is recognized in the period the related services are provided.

From time to time, we make payments to entities that are also customers under a revenue contract. These payments are primarily comprised of (i) Customer Inducements and (ii) payments to customers of our ALM business under revenue sharing arrangements for the remarketing of the customer's disposed IT assets. Customer Inducements do not represent payments for a distinct service, and, as such, are treated as a reduction of the transaction price over periods ranging from one to 10 years. Payments for disposed IT assets are for a distinct good and, as such, are expensed as cost of sales in the period the revenue share is known or estimable.

The costs associated with the initial movement of customer records into physical storage and certain commissions are considered costs to fulfill or obtain customer contracts (collectively, "Contract Costs"). The following describes our significant Contract Costs:

INTAKE COSTS (AND ASSOCIATED DEFERRED REVENUE)

The costs of the initial intake of customer records into physical storage ("Intake Costs") are deferred and amortized as a component of depreciation and amortization in our Consolidated Statements of Operations generally over three years, consistent with the transfer of the performance obligation to the customer to which the asset relates. In instances where such Intake Costs are billed to the customer, the associated revenue is deferred and recognized over the same three-year period.

			IRON MOUNTAIN 2023 FORM 10-K			89

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

COMMISSIONS

Certain commission payments that are directly associated with the fulfillment of long-term contracts are capitalized and amortized as a component of depreciation and amortization in our Consolidated Statements of Operations generally over three years, consistent with the transfer of the performance obligation to the customer to which the asset relates. We also apply the practical expedient to expense certain commission payments as incurred when the amortization period for those commission payments is one year or less.

Contract Costs, which are included as a component of Other within Other Assets, Net as of December 31, 2023 and 2022 are as follows:

						DECEMBER 31, 2023																		DECEMBER 31, 2022
DESCRIPTION						GROSS CARRYING AMOUNT						ACCUMULATED AMORTIZATION						NET CARRYING AMOUNT						GROSS CARRYING AMOUNT						ACCUMULATED AMORTIZATION						NET CARRYING AMOUNT
Intake Costs asset						$	76,150					$	(39,617)					$	36,533					$	68,345					$	(42,132)					$	26,213
Commissions asset						156,639						(64,279)						92,360						133,145						(58,949)						74,196

Amortization expense associated with the Intake Costs and Commissions assets for the years ended December 31, 2023, 2022 and 2021 are as follows:

						YEAR ENDED DECEMBER 31,
DESCRIPTION						2023						2022						2021
Intake Costs asset						$	18,904					$	18,117					$	17,530
Commissions asset						43,413						40,612						30,739

Estimated amortization expense for Contract Costs is as follows:

YEAR						ESTIMATED AMORTIZATION
2024						$	61,379
2025						44,161
2026						23,353

Deferred revenue liabilities are reflected as follows in our Consolidated Balance Sheets:

									DECEMBER 31,
DESCRIPTION			LOCATION IN BALANCE SHEET						2023						2022
Deferred revenue - Current			Deferred revenue						$	325,665					$	328,910
Deferred revenue - Long-term			Other Long-term Liabilities						100,770						32,960

DATA CENTER LESSOR CONSIDERATIONS

Our Global Data Center Business features storage rental provided to customers at contractually specified rates over a fixed contractual period. Our data center revenue contracts are accounted for in accordance with ASC 842. ASC 842 provides a practical expedient which allows lessors to account for nonlease components with the related lease component if both the timing and pattern of transfer are the same for nonlease components and the lease component, and the lease component, if accounted for separately, would be classified as an operating lease. The single combined component is accounted for under ASC 842 if the lease component is the predominant component and is accounted for under ASC 606 if the nonlease components are the predominant components. We have elected to take this practical expedient. Our data center revenue contracts may contain Consumer Price Index rent escalation clauses. Consumer Price Index rent escalation clauses are considered variable lease payments and are recognized as income in the period earned.

90			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

Storage rental revenue associated with our Global Data Center Business for the years ended December 31, 2023, 2022 and 2021 are as follows:

						YEAR ENDED DECEMBER 31,
						2023						2022						2021
Storage rental revenue						$	474,066					$	372,208					$	289,592

The revenue related to the service component of our Global Data Center Business is recognized in the period the related services are provided.

The future minimum lease payments we expect to receive under non-cancellable data center operating leases for which we are the lessor, excluding month to month leases, for the next five years are as follows:

YEAR						FUTURE MINIMUM LEASE PAYMENTS
2024						$	393,046
2025						388,491
2026						375,800
2027						342,441
2028						296,270

T. STOCK-BASED COMPENSATION

We record stock-based compensation expense, utilizing the straight-line method, for the cost of stock options, restricted stock units ("RSUs"), and performance units ("PUs") (together, "Employee Stock-Based Awards").

RETIREMENT ELIGIBLE CRITERIA

For our Employee Stock-Based Awards made on or after March 1, 2022, we have included the following retirement provision:

• Upon an employee’s retirement on or after attaining age 55 with at least five years of service, if the sum of (i) the award recipient’s age at retirement and (ii) the award recipient’s years of service with us totals at least 65, the award recipient is entitled to continued vesting of any outstanding Employee Stock-Based Awards, provided that their retirement occurs on or after a minimum of six months from the grant date (the "Retirement Criteria").

• Accordingly, (i) grants of Employee Stock-Based Awards to an employee who has met the Retirement Criteria on or before the date of grant, or will meet the Retirement Criteria before the six month anniversary in the year of the grant, will be expensed over six months from the date of grant and (ii) grants of Employee Stock-Based Awards to employees who will meet the Retirement Criteria during the award’s normal vesting period will be expensed between the date of grant and the date upon which the award recipient meets the Retirement Criteria.

• Stock options and RSUs granted to award recipients who meet the Retirement Criteria will be delivered to the award recipient based upon the original vesting schedule. If an award recipient retires and has met the Retirement Criteria, stock options will remain exercisable until the original expiration date of the stock options. PUs granted to award recipients who meet the Retirement Criteria will be delivered in accordance with the original vesting schedule of the applicable PU award and remain subject to the same performance conditions.

			IRON MOUNTAIN 2023 FORM 10-K			91

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

Stock-based compensation expense for Employee Stock-Based Awards included in the accompanying Consolidated Statements of Operations for the years ended December 31, 2023, 2022 and 2021 is as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Stock-based compensation expense			$	73,799					$	56,861					$	61,001
Stock-based compensation expense, after tax			68,309						52,600						59,243

The substantial majority of stock-based compensation expense for Employee Stock-Based Awards is included in Selling, general and administrative expenses in the accompanying Consolidated Statements of Operations.

STOCK OPTIONS

Options are generally granted with exercise prices equal to the market price of the stock on the date of grant; however, in certain instances, options are granted at exercise prices greater than the market price of the stock on the date of grant. We issue options that become exercisable ratably over a period three years from the date of grant and have a contractual life of 10 years from the date of grant, unless the holder’s employment is terminated sooner. Our non-employee directors are considered employees for purposes of our stock option plans and stock option reporting.

Our equity compensation plans generally provide that, upon a vesting change in control (as defined in each plan), any unvested options and other awards granted thereunder shall vest immediately if an employee is terminated as a result of the change in control or terminates their own employment for good reason (as defined in each plan). On January 20, 2015, our stockholders approved the adoption of the Iron Mountain Incorporated 2014 Stock and Cash Incentive Plan, as amended (the "2014 Plan").

In May 2021, our stockholders approved an amendment to the 2014 Plan to (i) increase the number of shares of our common stock authorized for issuance thereunder by 8,000,000 from 12,750,000 to 20,750,000, (ii) extend the termination date of the 2014 Plan from May 24, 2027 to May 12, 2031, (iii) provide that, other than in specified circumstances, no equity-based award will vest before the first anniversary of the date of grant and (iv) provide that dividends and dividend equivalents are not paid with respect to stock options or stock appreciation rights.

A total of 20,750,000 shares of common stock have been reserved for grants of options and other rights under our various stock incentive plans, including the 2014 Plan. The number of shares available for grant under our various stock incentive plans at December 31, 2023 was 6,204,098.

The fair value of stock options granted in 2023, 2022 and 2021 was $10.98, $7.44 and $3.23 per share, respectively. These values were estimated on the date of grant using the Black-Scholes option pricing model. The assumptions used for stock option grants in the years ended December 31, 2023, 2022 and 2021 are as follows:

						YEAR ENDED DECEMBER 31,
STOCK OPTION GRANT ASSUMPTIONS						2023						2022						2021
Expected volatility(1)						29.1		%				28.0		%				28.3		%
Risk-free interest rate(2)						3.92		%				1.72		%				1.45		%
Expected dividend yield(3)						5		%				5		%				7		%
Expected life(4)						10.0 years						10.0 years						10.0 years

(1)Expected volatility is calculated utilizing daily historical volatility over a period that equates to the expected life of the option.

(2)Risk-free interest rate is based on the United States Treasury interest rates whose term is consistent with the expected life (estimated period of time outstanding) of the stock options.

(3)Expected dividend yield is considered in the option pricing model and represents our annualized expected per share dividends over the trade price of our common stock at the date of grant.

(4)Expected life of the stock options granted is estimated using the historical exercise behavior of employees.

92			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

A summary of stock option activity for the year ended December 31, 2023 is as follows:

			OPTIONS						WEIGHTED AVERAGE EXERCISE PRICE						WEIGHTED AVERAGE REMAINING CONTRACTUAL TERM (YEARS)						AGGREGATE INTRINSIC VALUE
Outstanding at December 31, 2022			4,226,319						$	36.89
Granted			157,132						52.58
Exercised			(322,854)						32.66
Outstanding at December 31, 2023			4,060,597						$	37.84					4.44						$	130,548
Options exercisable at December 31, 2023			3,619,289						$	36.85					3.98						$	119,903
Options expected to vest			441,308						$	45.86					8.20						$	10,645

RESTRICTED STOCK UNITS

Our RSUs generally have a vesting period of three years from the date of grant. However, RSUs granted to our non-employee directors vest immediately upon grant. All RSUs accrue dividend equivalents associated with the underlying stock as we declare dividends. Dividends will generally be paid to holders of RSUs in cash upon the vesting date of the associated RSU and will be forfeited if the RSU does not vest. The fair value of RSUs is the excess of the market price of our common stock at the date of grant over the holder's purchase price (which is typically zero).

The fair value of RSUs vested during the years ended December 31, 2023, 2022 and 2021 are as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Fair value of RSUs vested			$	32,664					$	27,078					$	29,332

A summary of RSU activity for the year ended December 31, 2023 is as follows:

			RSUs						WEIGHTED-AVERAGE GRANT-DATE FAIR VALUE
Non-vested at December 31, 2022			1,306,115						$	43.43
Granted			1,035,583						53.02
Vested			(762,683)						42.83
Forfeited			(218,751)						48.63
Non-vested at December 31, 2023			1,360,264						$	50.24

PERFORMANCE UNITS

The PUs we issue vest based on our performance against predefined operational performance and relative total shareholder return based targets over a three-year performance period. The vesting is subject to a minimum level of return on invested capital in the third year of the performance period, and the number of PUs earned is based on certain metrics determined at the outset of the performance period.

			IRON MOUNTAIN 2023 FORM 10-K			93

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

For grants issued in 2023 and 2022, the number of PUs earned is based on:

• either (i) the revenue performance for each year averaged at the end of the three-year performance period, or (ii) if (a) absolute total shareholder return is positive at the end of the three-year performance period and (b) a predetermined revenue hurdle is achieved in the third year of the performance period, then the revenue performance achieved in the third year of the performance period; and

• the total return on our common stock relative to the Morgan Stanley Capital International (“MSCI”) United States REIT Index.

For grants issued in 2021, the number of PUs earned is based on:

• the revenue performance for each year averaged at the end of the three-year performance period;

• the revenue exit rate of new products in the last quarter of the three-year performance period; and

• the total return on our common stock relative to the MSCI United States REIT Index.

The number of PUs earned for grants made in 2023 and 2022 will range from 0% to approximately 350% of the initial award, and the number of PUs earned for grants made in 2021 will range from 0% to 200%.

All of our PUs will be settled in shares of our common stock and are subject to cliff vesting three years from the date of the original PU grant. As detailed above, PUs granted are subject to the Retirement Criteria. PUs are generally expensed over the three-year performance period, unless they are granted to a recipient who meets the Retirement Criteria, for which expense will be recognized as described above. PUs granted to recipients who meet the Retirement Criteria will continue to vest and be delivered in accordance with the original vesting schedule of the applicable PU award and remain subject to the same performance conditions.

All PUs accrue dividend equivalents associated with the underlying stock as we declare dividends. Dividends will generally be paid to holders of PUs in cash upon the settlement date of the associated PU and will be forfeited if the PU does not vest.

During the years ended December 31, 2023, 2022 and 2021, we issued 641,412, 435,675 and 488,953 PUs, respectively. We forecast the likelihood of achieving the predefined targets for our PUs in order to calculate the expected PUs to be earned. We record a compensation charge based on either the forecasted PUs to be earned (during the performance period) or the actual PUs earned (at the three-year anniversary of the grant date) over the vesting period for each of the awards. The fair value of PUs based on our performance against predefined targets is the excess of the market price of our common stock at the date of grant over the purchase price (which is typically zero). For PUs earned based on a market condition, we utilize a Monte Carlo simulation to fair value these awards at the date of grant.

The fair value of earned PUs that vested during the years ended December 31, 2023, 2022 and 2021 is as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Fair value of earned PUs that vested			$	34,896					$	20,059					$	29,701

A summary of PU activity for the year ended December 31, 2023 is as follows:

			ORIGINAL PU AWARDS						PU ADJUSTMENT**(1)**						TOTAL PU AWARDS						WEIGHTED-AVERAGE GRANT-DATE FAIR VALUE
Non-vested at December 31, 2022			830,173						(484,550)						345,623						$	45.65
Granted			641,412						—						641,412						55.76
Prior year grant adjustments for performance(1)			—						160,993						160,993						42.66
Vested			(615,588)						—						(615,588)						56.69
Forfeited			(51,087)						—						(51,087)						53.60
Non-vested at December 31, 2023			804,910						(323,557)						481,353						$	43.16

(1)Represents an increase or decrease in the number of original PUs awarded based on either the final performance criteria or market condition achievement at the end of the performance period of such PUs.

94			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

EMPLOYEE STOCK PURCHASE PLAN

We offer an Employee Stock Purchase Plan ("ESPP") in which participation is available to substantially all United States and Canadian employees who meet certain service eligibility requirements. Shares of our common stock may be purchased by eligible employees at six-month intervals at 95% of the fair market price at the end of each six-month period, without a look-back feature, up to a maximum of 15% of their gross compensation during the offering period. We do not recognize compensation expense for the ESPP shares purchased. The number of shares of Common Stock authorized for issuance under our ESPP is 2,000,000. For the years ended December 31, 2023, 2022 and 2021, there were 120,647, 112,486 and 112,297 shares, respectively, purchased under the ESPP. As of December 31, 2023, we have 870,857 shares available under the ESPP.

As of December 31, 2023, unrecognized compensation cost related to the unvested portion of our Employee Stock-Based Awards, inclusive of our estimated achievement of the performance metrics, was $61,799 and is expected to be recognized over a weighted-average period of 1.9 years.

We issue shares of our common stock for the exercises of stock options, and the vesting of RSUs, PUs and shares of our common stock under our ESPP from unissued reserved shares.

U. ACQUISITION AND INTEGRATION COSTS

Acquisition and integration costs represent operating expenditures directly associated with the closing and integration activities of our business acquisitions that have closed, or are highly probable of closing, and include (i) advisory, legal and professional fees to complete business acquisitions and (ii) costs to integrate acquired businesses into our existing operations, including move, severance and system integration costs (collectively, "Acquisition and Integration Costs"). Acquisition and integration costs for the years ended December 31, 2023, 2022 and 2021 were $25,875, $47,746 and $12,764, respectively.

V. OTHER EXPENSE (INCOME), NET

Other expense (income), net for the years ended December 31, 2023, 2022 and 2021 consists of the following:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Foreign currency transaction losses (gains), net(1)			$	36,799					$	(61,684)					$	(15,753)
Debt extinguishment expense			—						671						—
Other, net(2)(3)(4)			71,841						(8,768)						(177,051)
Other expense (income), net			$	108,640					$	(69,781)					$	(192,804)

(1)The gain or loss on foreign currency transactions, calculated as the difference between the historical exchange rate and the exchange rate at the applicable measurement date, includes gains or losses primarily related to (i) certain foreign currency denominated intercompany obligations of our foreign subsidiaries to us and between our foreign subsidiaries, which are not considered permanently invested, and (ii) borrowings in certain foreign currencies under the Revolving Credit Facility (as defined in Note 7).

(2)Other, net for the year ended December 31, 2023 consists primarily of a loss of approximately $38,000 associated with the remeasurement to fair value of our previously held equity interest in the Clutter JV (as defined and discussed in Note 5), as well as losses on our equity method investments and the change in value of the Deferred Purchase Obligation.

(3)Other, net for the year ended December 31, 2022 consists primarily of (i) a gain of approximately $93,600 associated with the remeasurement of the Deferred Purchase Obligation to the present value of our best estimate of fair value and (ii) a gain of approximately $35,800 associated with the Clutter Transaction (as defined in Note 5), partially offset by (iii) a loss of approximately $105,800 associated with the OSG Deconsolidation (as defined in Note 4) and (iv) losses on our equity method investments.

(4)Other, net for the year ended December 31, 2021 consists primarily of (i) a gain of approximately $179,000 associated with our IPM Divestment (as defined in Note 4) and (ii) a gain of approximately $20,300 associated with the loss of control and related deconsolidation, as of May 18, 2021, of one of our wholly-owned Netherlands subsidiaries, for which we had value-added tax liability exposure that was recorded in 2019, partially offset by (iii) losses on our equity method investments.

			IRON MOUNTAIN 2023 FORM 10-K			95

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

W. INCOME TAXES

Accounting for income taxes requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the tax and financial reporting bases of assets and liabilities and for loss and credit carryforwards. Valuation allowances are provided when recovery of deferred tax assets does not meet the more likely than not standard as defined in GAAP. We have elected to recognize interest and penalties associated with uncertain tax positions as a component of the Provision (benefit) for income taxes in the accompanying Consolidated Statements of Operations.

X. INCOME (LOSS) PER SHARE—BASIC AND DILUTED

Basic income (loss) per common share is calculated by dividing income (loss) by the weighted average number of common shares outstanding. The calculation of diluted income (loss) per share is consistent with that of basic income (loss) per share but gives effect to all potential common shares (that is, securities such as stock options, RSUs, PUs, warrants or convertible securities) that were outstanding during the period, unless the effect is antidilutive.

The calculation of basic and diluted income (loss) per share for the years ended December 31, 2023, 2022 and 2021 is as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Net Income (Loss)			$	187,263					$	562,149					$	452,725
Less: Net Income (Loss) Attributable to Noncontrolling Interests			3,029						5,168						2,506
Net Income (Loss) Attributable to Iron Mountain Incorporated (utilized in numerator of Earnings Per Share calculation)			$	184,234					$	556,981					$	450,219
Weighted-average shares—basic			291,936,000						290,812,000						289,457,000
Effect of dilutive potential stock options			1,435,000						1,125,068						645,886
Effect of dilutive potential RSUs and PUs			594,000						507,109						872,204
Weighted-average shares—diluted			293,965,000						292,444,177						290,975,090
Net Income (Loss) Per Share Attributable to Iron Mountain Incorporated:
Basic			$	0.63					$	1.92					$	1.56
Diluted			$	0.63					$	1.90					$	1.55
Antidilutive stock options, RSUs and PUs, excluded from the calculation			81,817						305,527						1,447,722

Y. NEW ACCOUNTING PRONOUNCEMENTS

RECENTLY ADOPTED ACCOUNTING PRONOUNCEMENTS

In December 2021, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2021-08, Business Combinations (Topic 805), Accounting for Contract Assets and Contract Liabilities from Contracts with Customers ("ASU 2021-08"). ASU 2021-08 requires that an entity recognize and measure contract assets and contract liabilities acquired in a business combination in accordance with ASU 2014-09 and for the related revenue contracts in accordance with ASU 2014-09 as if it had originated the contracts. We adopted ASU 2021-08 on January 1, 2023 on a prospective basis, and there was no material impact on our consolidated financial statements.

96			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)

OTHER AS YET ADOPTED ACCOUNTING PRONOUNCEMENTS

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740), Improvements to Income Tax Disclosures ("ASU 2023-09") to provide disaggregated income tax disclosures on the rate reconciliation and income taxes paid. Further, certain requirements related to uncertain tax positions and unrecognized deferred tax liabilities are eliminated. The amendments in this update should be applied on a prospective basis, with retrospective application permitted. ASU 2023-09 will be effective for us on January 1, 2025, with early adoption permitted. We do not expect ASU 2023-09 to have a material impact on our consolidated financial statements.

In November 2023, the FASB issued ASU No. 2023-07, Improvements to Reportable Segments Disclosures ("ASU 2023-07") to provide more detail in the disclosures for reportable segments. The main provisions of ASU 2023-07 requires (i) enhanced disclosures about significant segment expenses, (ii) extension of certain annual disclosures to interim periods and (iii) certain qualitative information on the chief operating decision maker. The amendments in this update will be effective for us on January 1, 2024, with early adoption permitted. We do not expect ASU 2023-07 to have a material impact on our consolidated financial statements.

In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848) ("ASU 2020-04"). ASU 2020-04 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions, for a limited period of time, to ease the potential burden of recognizing the effects of reference rate reform on financial reporting. The amendments in ASU 2020-04 apply to contracts, hedging relationships and other transactions that reference the London Inter-Bank Offered Rate ("LIBOR") or another reference rate expected to be discontinued due to the global transition away from LIBOR and certain other interbank offered rates. Under ASU 2020-04, an entity could elect to apply the amendments beginning March 12, 2020 through December 31, 2022. In December 2022, the FASB issued ASU No. 2022-06, Reference Rate Reform (Topic 848), Deferral of the Sunset Date of Topic 848 ("ASU 2022-06") to defer the sunset date of Topic 848 from December 31, 2022 to December 31, 2024, after which entities will no longer be permitted to apply the relief in Topic 848. We are currently evaluating these amendments as they relate to our contracts, hedging relationships and other transactions that reference LIBOR, as well as the impact of ASU 2020-04 and ASU 2022-06 on our consolidated financial statements, but we do not expect the impact to be material.

3. ACQUISITIONS

We account for acquisitions using the acquisition method of accounting, and, accordingly, the assets and liabilities acquired are recorded at their estimated fair values and the results of operations for each acquisition have been included in our consolidated results from their respective acquisition dates.

A. ACQUISITIONS COMPLETED DURING THE YEAR ENDED DECEMBER 31, 2023

WEB WERKS

On July 7, 2023, we made our final contractual investment in the Web Werks JV (as defined in Note 5) of approximately 3,750,000 Indian rupees (or approximately $45,300, based upon the exchange rate between the United States dollar and Indian rupee on the closing date of this investment) (the "Web Werks Transaction"). As a result of the Web Werks Transaction, our interest in the Web Werks JV increased to 63.39%, we assumed control of its board of directors and the financial results of the Web Werks JV are now consolidated within our Global Data Center Business segment. We recognized noncontrolling interests of approximately $78,600 based upon the fair value attributable to these interests at the time of the Web Werks Transaction, of which approximately $18,100 of the noncontrolling interests were determined to be a current liability and included as a component of Accrued expenses and other current liabilities on our Consolidated Balance Sheet at December 31, 2023.

			IRON MOUNTAIN 2023 FORM 10-K			97

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

3. ACQUISITIONS (CONTINUED)

CLUTTER

On June 29, 2023, in order to further expand our on-demand consumer storage business, we acquired 100% of the outstanding shares of Clutter Intermediate, Inc. and control of all assets of the Clutter JV (collectively, "Clutter") for total consideration of $60,600 (the “Clutter Acquisition”). The financial results of the Clutter JV are now consolidated within our Global RIM Business segment. In October 2023, we sold 15% of the equity interests in Clutter to certain former stakeholders of the Clutter JV for a total consideration of $7,500, which represents the fair value attributable to these interests, which is included as a component of Redeemable Noncontrolling Interests on our Consolidated Balance Sheet at December 31, 2023.

B. ACQUISITIONS CLOSED SUBSEQUENT TO DECEMBER 31, 2023

REGENCY TECHNOLOGIES

On January 3, 2024, in order to expand our ALM business, we acquired RSR Partners, LLC (doing business as Regency Technologies), an IT asset disposition services provider with operations throughout the United States, for an initial purchase price of approximately $200,000, with $125,000 paid at closing, funded by borrowings under the Revolving Credit Facility, and the remaining amount to be paid in 2025 (the "Regency Transaction"). The agreement for the Regency Transaction also includes potential performance-based contingent consideration, which would be payable in 2027, if earned. We will record a preliminary purchase price allocation for the assets acquired and liabilities assumed in connection with the Regency Transaction based on their estimated fair values as of the acquisition date. Given the Regency Transaction recently closed, the preliminary purchase price allocation is still in process and is incomplete as of this filing date.

C. ACQUISITIONS COMPLETED DURING THE YEAR ENDED DECEMBER 31, 2022

ITRENEW

On January 25, 2022, in order to expand our ALM operations, we acquired an approximately 80% interest in ITRenew at an agreed upon purchase price of $725,000, subject to certain working capital adjustments at, and subsequent to, the closing (the "ITRenew Transaction"). At closing, we paid $748,846 and acquired $30,720 of cash on hand, for a net purchase price of $718,126 for the ITRenew Transaction. The acquisition agreement provides us the option to purchase, and provides the shareholders of ITRenew the option to sell, the remaining approximately 20% interest in ITRenew as follows: (i) approximately 16% on or after the second anniversary of the ITRenew Transaction and (ii) approximately 4% on or after the third anniversary of the ITRenew Transaction (collectively, the "Remaining Interests"). The total payments for the Remaining Interests, based on the achievement of certain targeted performance metrics, will be no less than $200,000 and no more than $531,000 (the "Deferred Purchase Obligation"). From January 25, 2022, we consolidate 100% of the revenues and expenses associated with this business. The current and long-term portions of the Deferred Purchase Obligation are reflected as components of Accrued expenses and other current liabilities and Other long-term liabilities, respectively, in our Consolidated Balance Sheets at December 31, 2023 and December 31, 2022, and, accordingly, we have not reflected any non-controlling interests associated with the ITRenew Transaction as the Remaining Interests have non-substantive equity interest rights. Subsequent increases or decreases in the fair value estimate of the Deferred Purchase Obligation are included as a component of Other expense (income), net in our Consolidated Statements of Operations until the Deferred Purchase Obligation is settled or paid. See Note 2.v.

98			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

3. ACQUISITIONS (CONTINUED)

The unaudited consolidated pro forma financial information (the "Pro Forma Financial Information") below summarizes the combined results of Iron Mountain and ITRenew on a pro forma basis as if the ITRenew Transaction had occurred on January 1, 2021. The Pro Forma Financial Information is presented for informational purposes and is not necessarily indicative of the results of operations that would have been achieved if the acquisition had taken place on January 1, 2021. The Pro Forma Financial Information, for the periods presented, includes purchase accounting adjustments (including amortization of acquired customer and supplier intangible assets and depreciation of acquired property, plant and equipment) and related tax effects. Through December 31, 2022, we and ITRenew collectively incurred $59,370 of operating expenditures to complete the ITRenew Transaction (including advisory and professional fees). These operating expenditures have been reflected within the results of operations in the Pro Forma Financial Information as if they were incurred on January 1, 2021.

			YEAR ENDED DECEMBER 31,
			2022						2021
Total Revenues			$	5,121,548					$	4,939,511
Income from Continuing Operations			571,381						391,625

In addition to our acquisition of ITRenew, we completed certain other acquisitions during the years ended December 31, 2023, 2022 and 2021. The Pro Forma Financial Information does not reflect these acquisitions due to the insignificant impact of these acquisitions on our consolidated results of operations.

XDATA PROPERTIES

On October 5, 2022, in order to further expand our data center operations in Europe, we completed the acquisition of XData Properties S.L.U., a data center colocation space and solutions provider with a data center in Spain, which we accounted for as an asset acquisition, for (i) cash consideration of 78,900 Euros (or approximately $78,200, based upon the exchange rate between the Euro and the United States dollar on the closing date of this acquisition), subject to adjustments, and (ii) up to 10,000 Euros (or approximately $9,900, based upon the exchange rate between the Euro and the United States dollar on the closing date of this acquisition) of additional consideration, payable based on the achievement of certain power connection milestones through December 2024.

D. ACQUISITIONS COMPLETED DURING THE YEAR ENDED DECEMBER 31, 2021

On September 15, 2021, in order to further expand our records management operations in the Middle East and North Africa, we acquired Information Fort, LLC, a records and information management provider, for approximately $90,300.

On September 23, 2021, in order to further enhance our data center operations in Germany, we completed the acquisition of assets of a Frankfurt data center for approximately 77,900 Euros (or approximately $91,300, based upon the exchange rate between the Euro and the United States dollar on the closing date of this acquisition).

In addition to the transactions noted above, during the year ended December 31, 2021, in order to enhance our existing operations in the United Kingdom and Indonesia and to expand our operations into Morocco, we completed the acquisition of two records management companies and one art storage company for total cash consideration of approximately $45,100.

			IRON MOUNTAIN 2023 FORM 10-K			99

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

3. ACQUISITIONS (CONTINUED)

E. PURCHASE PRICE ALLOCATION

A summary of the cumulative consideration paid and the allocation of the purchase price paid for all of our acquisitions (including asset acquisitions) in each respective year is as follows:

			2023						2022																		2021
			TOTAL						ITRENEW						OTHER FISCAL YEAR 2022 ACQUISITIONS						TOTAL						TOTAL
Cash Paid (gross of cash acquired)(1)			$	88,635					$	749,596					$	85,170					$	834,766					$	224,192
Fair Value of Noncontrolling Interests(2)			78,598						—						—						—						3,878
Fair Value of Previously Held Equity Interest(2)			99,718						—						—						—						—
Deferred Purchase Obligation, Purchase Price Holdbacks and Other(3)			4,790						275,100						13,637						288,737						2,534
Settlement of Pre-Existing Relationships			21,641						—						—						—						—
Total Consideration			293,382						1,024,696						98,807						1,123,503						230,604
Fair Value of Identifiable Assets Acquired and Liabilities Assumed:
Cash and Cash Equivalents			49,716						30,694						963						31,657						20,194
Accounts Receivable, Prepaid Expenses and Other Assets			36,274						71,612						3,947						75,559						26,911
Property, Plant and Equipment			140,668						7,541						93,722						101,263						150,095
Customer and Supplier Relationship Intangible Assets(4)			14,330						487,600						3,672						491,272						35,181
Other Intangible Assets			8,046						47,300						1,442						48,742						9,656
Operating Lease Right-of-Use Assets			29,046						29,545						3,135						32,680						40,848
Debt Assumed			(22,413)						—						—						—						(9,026)
Accounts Payable, Accrued Expenses and Other Liabilities			(19,323)						(60,157)						(2,069)						(62,226)						(22,733)
Operating Lease Liabilities			(29,046)						(29,545)						(3,135)						(32,680)						(40,848)
Deferred Income Taxes			(4,495)						(100,922)						(10,143)						(111,065)						(7,221)
Total Fair Value of Identifiable Net Assets Acquired			202,803						483,668						91,534						575,202						203,057
Goodwill Initially Recorded			$	90,579					$	541,028					$	7,273					$	548,301					$	27,547

(1)Cash paid for acquisitions, net of cash acquired in our Consolidated Statements of Cash Flows includes contingent and other payments of $2,930, $581 and $0 for the years ended December 31, 2023, 2022 and 2021, respectively, related to acquisitions made in the years prior to 2023, 2022 and 2021, respectively.

(2)The fair values of the noncontrolling interests and the previously held equity interest were determined to be the respective interest’s proportionate share of the fair value of net assets acquired as of the acquisition date.

(3)In 2022, Deferred purchase obligation, purchase price holdbacks and other includes $275,100 related to the original fair value estimate of the Deferred Purchase Obligation for the Remaining Interests.

(4)The weighted average lives of customer and supplier relationship intangible assets associated with acquisitions in 2023, 2022 and 2021 were four years, 12 years and 11 years, respectively.

Allocations of the purchase price for acquisitions are based on estimates of the fair value of the net assets acquired and are subject to adjustment upon the finalization of the purchase price allocations. The accounting for business combinations requires estimates and judgments regarding expectations for future cash flows of the acquired business, and the allocations of those cash flows to identifiable tangible and intangible assets, in determining the assets acquired and liabilities assumed. The fair values assigned to tangible and intangible assets acquired and liabilities assumed, including contingent consideration, are based on management’s best estimates and assumptions, as well as other information compiled by management, including valuations that utilize customary valuation procedures and techniques. The estimates and assumptions underlying the initial valuations are subject to the collection of information necessary to complete the valuations within the measurement periods, which are up to one year from the respective acquisition dates.

100			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

3. ACQUISITIONS (CONTINUED)

As the valuation of certain assets and liabilities for purposes of purchase price allocations are preliminary in nature, they are subject to adjustment as additional information is obtained about the facts and circumstances regarding these assets and liabilities that existed at the acquisition date. The preliminary purchase price allocations that are not finalized as of December 31, 2023 relate to the final assessment of the fair values of property, plant and equipment and intangible assets associated with the acquisitions we closed during the year ended December 31, 2023. Any adjustments to our estimates of purchase price allocation will be made in the periods in which the adjustments are determined and the cumulative effect of such adjustments will be calculated as if the adjustments had been completed as of the acquisition dates. Purchase price allocation adjustments recorded during the fourth quarter of 2023 and year ended December 31, 2023 were not material to our balance sheet or results from operations.

4. DIVESTMENTS AND DECONSOLIDATIONS

OSG RECORDS MANAGEMENT (EUROPE) LIMITED DECONSOLIDATION

On March 24, 2022, as a result of our loss of control, we deconsolidated the businesses included in our acquisition of OSG, excluding Ukraine ("OSG Deconsolidation"). We recognized a loss of approximately $105,800 associated with the deconsolidation to Other expense (income), net in the first quarter of 2022 representing the difference between the net asset value prior to the deconsolidation and the subsequent remeasurement of the retained investment to a fair value of zero. We have concluded that the deconsolidation does not meet the criteria to be reported as discontinued operations in our consolidated financial statements, as it does not represent a strategic shift that will have a major effect on our operations and financial results.

INTELLECTUAL PROPERTY MANAGEMENT BUSINESS DIVESTMENT

On June 7, 2021, we sold our Intellectual Property Management ("IPM") business, which we predominantly operated in the United States, for total gross consideration of approximately $215,400 (the "IPM Divestment"). As a result of the IPM Divestment, we recorded a gain on sale of approximately $179,000 to Other expense (income), net during the year ended December 31, 2021, representing the excess of the fair value of the consideration received over the sum of the carrying value of the IPM business. We have concluded that the IPM Divestment does not meet the criteria to be reported as discontinued operations in our consolidated financial statements, as our decision to divest this business does not represent a strategic shift that will have a major effect on our operations and financial results.

5. INVESTMENTS

CLUTTER JOINT VENTURE

In February 2022, the joint venture formed by MakeSpace Labs, Inc. and us (the "MakeSpace JV") entered into an agreement with Clutter, Inc. pursuant to which the equityholders of the MakeSpace JV contributed their ownership interests in the MakeSpace JV, and Clutter, Inc.’s shareholders contributed their ownership interests in Clutter, Inc., to create a newly formed venture (the "Clutter JV"). In exchange for our 49.99% interest in the MakeSpace JV, we received an approximate 27% interest in the Clutter JV (the "Clutter Transaction"). As a result of the Clutter Transaction, we recognized a gain related to our contributed interest in the MakeSpace JV of approximately $35,800, which was recorded to Other, net, a component of Other expense (income), net, during the year ended December 31, 2022.

On June 29, 2023, we completed the Clutter Acquisition. In connection with the Clutter Acquisition, our previously held approximately 27% interest in the Clutter JV was remeasured to fair value at the closing date of the Clutter Acquisition. As a result, we recognized a loss of approximately $38,000 to Other, net, a component of Other expense (income), net, during the second quarter of 2023.

			IRON MOUNTAIN 2023 FORM 10-K			101

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2022

(In thousands, except share and per share data)

5. INVESTMENTS (CONTINUED)

WEB WERKS JOINT VENTURE

In April 2021, we closed on an agreement to form a joint venture (the "Web Werks JV") with the shareholders of Web Werks India Private Limited, a colocation data center provider in India. During the years ended December 31, 2022 and 2021, we made two investments totaling approximately 7,500,000 Indian rupees (or approximately $96,200, based upon the exchange rates between the United States dollar and Indian rupee on the closing date of each investment) in exchange for a noncontrolling interest in the form of convertible preference shares in the Web Werks JV. In July 2023, we made our final contractual investment in the Web Werks JV. See Note 3.

JOINT VENTURE SUMMARY

The joint ventures referred to above are accounted for as equity method investments and are presented as a component of Other within Other assets, net in our Consolidated Balance Sheets. The carrying values and equity interests in our joint ventures at December 31, 2023 and 2022 are as follows:

						DECEMBER 31, 2023												DECEMBER 31, 2022
						CARRYING VALUE						EQUITY INTEREST						CARRYING VALUE						EQUITY INTEREST
Web Werks JV						$	—					—		%				$	98,278					53.58		%
Joint venture with AGC Equity Partners (the "Frankfurt JV")						57,874						20.00		%				37,194						20.00		%
Clutter JV						—						—		%				54,172						26.73		%

6. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES

Derivative instruments we are party to include: (i) interest rate swap agreements (which are designated as cash flow hedges) and (ii) cross-currency swap agreements (which are designated as net investment hedges).

INTEREST RATE SWAP AGREEMENTS DESIGNATED AS CASH FLOW HEDGES

We utilize interest rate swap agreements designated as cash flow hedges to limit our exposure to changes in interest rates on a portion of our floating rate indebtedness. Certain of our interest rate swap agreements have notional amounts that will increase with the underlying hedged transaction. Under our interest rate swap agreements, we receive variable rate interest payments associated with the notional amount of each interest rate swap, based upon the one-month Secured Overnight Financing Rate (“SOFR”), in exchange for the payment of fixed interest rates as specified in the interest rate swap agreements. Our interest rate swap agreements are marked to market at the end of each reporting period, representing the fair values of the interest rate swap agreements, and any changes in fair value are recognized as a component of Accumulated other comprehensive items, net. Unrealized gains are recognized as assets, while unrealized losses are recognized as liabilities.

In April 2023, in anticipation of the discontinuance of the LIBOR reference rate on June 30, 2023, we terminated interest rate swap agreements with notional amounts totaling $350,000 that were indexed to the one-month LIBOR benchmark rate. The terminated swap agreements had associated unrealized gains at the termination date of approximately $10,100. These gains are included in Accumulated other comprehensive items, net and will be reclassified into earnings as reductions to interest expense from the termination date through March 2024, the original maturity date of these interest rate swap agreements.

As of December 31, 2023 and 2022, we have approximately $520,000 and $354,800, respectively, in notional value outstanding on our interest rate swap agreements, with maturity dates ranging from October 2025 through February 2026.

102			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

6. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (CONTINUED)

CROSS-CURRENCY SWAP AGREEMENTS DESIGNATED AS A HEDGE OF NET INVESTMENT

We utilize cross-currency interest rate swaps to hedge the variability of exchange rate impacts between the United States dollar and the Euro. As of December 31, 2023 and 2022, we have approximately $509,200 and $469,200, respectively, in notional value outstanding on cross-currency interest rate swaps, with maturity dates ranging from August 2024 through February 2026.

We have designated these cross-currency swap agreements as hedges of net investments in certain of our Euro denominated subsidiaries and they require an exchange of the notional amounts at maturity. These cross-currency swap agreements are marked to market at the end of each reporting period, representing the fair values of the cross-currency swap agreements, and any changes in fair value are recognized as a component of Accumulated other comprehensive items, net. Unrealized gains are recognized as assets while unrealized losses are recognized as liabilities. The excluded component of our cross-currency swap agreements is recorded in Accumulated other comprehensive items, net and amortized to interest expense on a straight-line basis.

The fair value of derivative instruments recognized in our Consolidated Balance Sheets as of December 31, 2023 and 2022, by derivative instrument, are as follows:

DERIVATIVE INSTRUMENTS**(1)**						DECEMBER 31, 2023												DECEMBER 31, 2022
						Assets						Liabilities						Assets						Liabilities
Cash Flow Hedges*(2)*
Interest rate swap agreements						$	1,601					$	(3,273)					$	12,995					$	489
Net Investment Hedges*(3)*
Cross-currency swap agreements						4,758						(2,496)						38,401						—

(1)Our derivative assets are included as a component of (i) Prepaid expenses and other or (ii) Other within Other assets, net and our derivative liabilities are included as a component of (i) Accrued expenses and other current liabilities or (ii) Other long-term liabilities in our Consolidated Balance Sheets. As of December 31, 2023, $6,359 is included within Other assets, $2,496 is included within accrued expenses and other liabilities, and $3,273 is included within Other long-term liabilities. As of December 31, 2022, $2,606 is included within Prepaid expenses and other, $48,790 is included within Other assets and $489 is included within Other long-term liabilities.

(2)As of December 31, 2023, cumulative net gains recorded within Accumulated other comprehensive items, net associated with our interest rate swap agreements are $2,472, which include $2,528 related to our terminated interest rate swap agreements.

(3)As of December 31, 2023, cumulative net gains recorded within Accumulated other comprehensive items, net associated with our cross-currency swap agreements are $32,459, which include $30,197 related to the excluded component of our cross-currency swap agreements.

Unrealized (losses) gains recognized in Accumulated other comprehensive items, net during the years ending December 31, 2023, 2022 and 2021, by derivative instrument, are as follows:

						YEAR ENDED DECEMBER 31,
DERIVATIVE INSTRUMENTS						2023						2022						2021
Cash Flow Hedges
Interest rate swap agreements						$	(2,454)					$	20,186					$	13,382
Net Investment Hedges
Cross-currency swap agreements						(41,382)						28,044						38,998
Cross-currency swap agreements (excluded component)						21,097						9,100						—

			IRON MOUNTAIN 2023 FORM 10-K			103

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

6. DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES (CONTINUED)

Gains (losses) recognized in Net income during the years ending December 31, 2023, 2022 and 2021, by derivative instrument, are as follows:

									YEAR ENDED DECEMBER 31,
DERIVATIVE INSTRUMENTS			Location of gain (loss)						2023						2022						2021
Cash Flow Hedges
Interest rate swap agreements			Interest expense						$	7,580					$	—					$	—
Net Investment Hedges
Cross-currency swap agreements (excluded component)			Interest expense						(21,097)						(9,100)						—

104			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

7. DEBT

Long-term debt is as follows:

						DECEMBER 31, 2023																											DECEMBER 31, 2022
						DEBT (INCLUSIVE OF DISCOUNT)						UNAMORTIZED DEFERRED FINANCING COSTS						CARRYING AMOUNT						FAIR VALUE									DEBT (INCLUSIVE OF DISCOUNT)						UNAMORTIZED DEFERRED FINANCING COSTS						CARRYING AMOUNT						FAIR VALUE
Revolving Credit Facility(1)						$	—					$	(4,621)					$	(4,621)					$	—								$	1,072,200					$	(6,790)					$	1,065,410					$	1,072,200
Term Loan A(1)						228,125						—						228,125						228,125									240,625						—						240,625						240,625
Term Loan B due 2026(1)(2)						659,298						(2,498)						656,800						659,750									666,073						(3,747)						662,326						666,750
Term Loan B due 2031(1)(3)						1,191,000						(13,026)						1,177,974						1,200,000									—						—						—						—
Virginia 3 Term Loans(5)						101,218						(4,641)						96,577						101,218									—						—						—						—
Virginia 4/5 Term Loans(5)						16,338						(5,892)						10,446						16,338									—						—						—						—
Australian Dollar Term Loan (4)(5)						197,743						(482)						197,261						199,195									202,641						(633)						202,008						204,623
UK Bilateral Revolving Credit Facility(5)						178,239						—						178,239						178,239									169,361						—						169,361						169,361
37/8% GBP Senior Notes due 2025 (the "GBP Notes")(6)(8)(9)						509,254						(1,763)						507,491						489,108									483,888						(2,589)						481,299						445,206
47/8% Senior Notes due 2027 (the “47/8% Notes due 2027")(6)(7)(8)						1,000,000						(5,332)						994,668						967,500									1,000,000						(6,754)						993,246						917,500
51/4% Senior Notes due 2028 (the “51/4% Notes due 2028")(6)(7)(8)						825,000						(5,019)						819,981						800,250									825,000						(6,200)						818,800						754,875
5% Senior Notes due 2028 (the “5% Notes due 2028")(6)(7)(8)						500,000						(3,316)						496,684						478,750									500,000						(4,039)						495,961						450,000
7% Senior Notes due 2029 (the "7% Notes due 2029")(6)(7)(8)						1,000,000						(10,813)						989,187						1,027,500									—						—						—						—
47/8% Senior Notes due 2029 (the “47/8% Notes due 2029")(6)(7)(8)						1,000,000						(8,318)						991,682						945,000									1,000,000						(9,764)						990,236						865,000
51/4% Senior Notes due 2030 (the “51/4% Notes due 2030")(6)(7)(8)						1,300,000						(9,903)						1,290,097						1,241,500									1,300,000						(11,407)						1,288,593						1,111,500
41/2% Senior Notes due 2031 (the “41/2% Notes")(6)(7)(8)						1,100,000						(8,917)						1,091,083						995,500									1,100,000						(10,161)						1,089,839						891,000
5% Senior Notes due 2032 (the “5% Notes due 2032")(6)(8)(10)						750,000						(11,206)						738,794						684,375									750,000						(12,511)						737,489						622,500
55/8% Senior Notes due 2032 (the “55/8% Notes")(6)(7)(8)						600,000						(4,985)						595,015						567,000									600,000						(5,566)						594,434						520,500
Real Estate Mortgages, Financing Lease Liabilities and Other(11)						519,907						(403)						519,504						519,907									425,777						(578)						425,199						425,777
Accounts Receivable Securitization Program(12)						358,500						(317)						358,183						358,183									314,700						(531)						314,169						314,700
Total Long-term Debt						12,034,622						(101,452)						11,933,170															10,650,265						(81,270)						10,568,995
Less Current Portion						(120,670)						—						(120,670)															(87,546)						—						(87,546)
Long-term Debt, Net of Current Portion						$	11,913,952					$	(101,452)					$	11,812,500														$	10,562,719					$	(81,270)					$	10,481,449

(1)The capital stock or other equity interests of our United States subsidiaries representing the substantial majority of our United States operations, and up to 66% of the capital stock or other equity interests of most of our first-tier foreign subsidiaries, are pledged to secure these debt instruments, together with all intercompany obligations (including promissory notes) of subsidiaries owed to us or to one of our United States subsidiary guarantors. In addition, Iron Mountain Canada Operations ULC has pledged 66% of the capital stock of its subsidiaries, and all intercompany obligations (including promissory notes) owed to or held by it, to secure the Revolving Credit Facility. The fair value (Level 2 and Level 3 of fair value hierarchy described at Note 2.p.) of these debt instruments approximates the carrying value (as borrowings under these debt instruments are based on current variable market interest rates (plus a margin that is subject to change based on our consolidated leverage ratio), as of December 31, 2023 and 2022 (collectively, the “Credit Agreement Collateral”).

(2)The amount of debt for the Term Loan B due 2026 (as defined below) reflects an unamortized original issue discount of $452 and $677 as of December 31, 2023 and 2022, respectively.

(3)The amount of debt for the Term Loan B due 2031 (as defined below) reflects an unamortized original issue discount of $9,000 as of December 31, 2023.

(4)The amount of debt for the AUD Term Loan reflects an unamortized original issue discount of $1,452 and $1,982 as of December 31, 2023 and 2022, respectively.

			IRON MOUNTAIN 2023 FORM 10-K			105

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

7. DEBT (CONTINUED)

(5)The fair value (Level 2 of fair value hierarchy described at Note 2.p.) of this debt instrument approximates the carrying value as borrowings under this debt instrument are based on a current variable market interest rate.

(6)The fair values (Level 2 of fair value hierarchy described at Note 2.p.) of these debt instruments are based on quoted market prices for comparable notes on December 31, 2023 and 2022, respectively.

(7)Collectively, the "Parent Notes". IMI is the direct obligor on the Parent Notes, which are fully and unconditionally guaranteed, on a senior basis, by IMI’s United States subsidiaries that represent the substantial majority of our United States operations (the "Note Guarantors"). These guarantees are joint and several obligations of the Note Guarantors. The remainder of our subsidiaries do not guarantee the Parent Notes.

(8)Collectively, the "Unregistered Notes". The Unregistered Notes have not been registered under the Securities Act of 1933, as amended (the "Securities Act"), or under the securities laws of any other jurisdiction. Unless they are registered, the Unregistered Notes may be offered only in transactions that are exempt from registration under the Securities Act or the securities laws of any other jurisdiction.

(9)Iron Mountain (UK) PLC ("IM UK") is the direct obligor on the GBP Notes, which are fully and unconditionally guaranteed, on a senior basis, by IMI and the Note Guarantors. These guarantees are joint and several obligations of IMI and the Note Guarantors. The remainder of our subsidiaries do not guarantee the GBP Notes.

(10)Iron Mountain Information Management Services, Inc. ("IMIM Services") is the direct obligor on the 5% Notes due 2032, which are fully and unconditionally guaranteed, on a senior basis, by IMI and the Note Guarantors. These guarantees are joint and several obligations of IMI and the Note Guarantors. The remainder of our subsidiaries do not guarantee the 5% Notes due 2032.

(11)We believe the fair value (Level 2 of fair value hierarchy described at Note 2.p.) of this debt approximates its carrying value as these borrowings are based on current market interest rates. This debt includes the following:

			DECEMBER 31, 2023						DECEMBER 31, 2022
Real estate mortgages(1)			$	57,753					$	58,355
Financing lease liabilities(2)			349,865						332,905
Other notes and other obligations(3)			112,289						34,517
			$	519,907					$	425,777

(1)Bear interest at approximately 3.6% at both December 31, 2023 and 2022, and includes $50,000 outstanding under our Mortgage Securitization Program at both December 31, 2023 and 2022.

(2)Bear a weighted average interest rate of 6.1% and 5.2% at December 31, 2023 and 2022.

(3)These notes and other obligations, which were assumed by us as a result of certain acquisitions bear a weighted average interest rate of 8.5% and 10.1% at December 31, 2023 and 2022.

(12) The Accounts Receivable Securitization Special Purpose Subsidiaries are the obligors under this program. We believe the fair value (Level 2 of fair value hierarchy described at Note 2.p.) of this debt approximates its carrying value as borrowings under this debt instrument are based on a current variable market interest rate.

A. CREDIT AGREEMENT

Our credit agreement (the "Credit Agreement") consists of a revolving credit facility (the "Revolving Credit Facility"), a term loan A facility (the "Term Loan A") and two term loan B facilities (the "Term Loan B due 2026" and the "Term Loan B due 2031").

The Revolving Credit Facility enables IMI and certain of its subsidiaries to borrow an aggregate outstanding amount not to exceed $2,250,000 in United States dollars and (subject to sublimits) Canadian dollars. Additionally, the Credit Agreement permits us to incur incremental indebtedness thereunder by adding new term loans or revolving loans or by increasing the principal amount of any existing loans thereunder. The Revolving Credit Facility and the Term Loan A are scheduled to mature on March 18, 2027, at which point all obligations become due. On March 18, 2022, we borrowed the full amount of the Term Loan A of $250,000. The Term Loan A is to be paid in quarterly installments in an amount equal to $3,125 per quarter. Iron Mountain Information Management, LLC ("IMIM"), a wholly-owned subsidiary of IMI, is the borrower under the Term Loan B due 2026, which has a principal amount of $700,000. The Term Loan B due 2026, which matures on January 2, 2026, was issued at 99.75% of par. Principal payments on the Term Loan B due 2026 are to be paid in quarterly installments of $1,750.

In December 2023, we entered into the Term Loan B due 2031 in the principal amount of $1,200,000, of which IMIM borrowed the full amount. The Term Loan B due 2031 was issued at 99.25% of par and matures on January 31, 2031. The aggregate net proceeds of approximately $1,181,000, after paying commissions to the joint lead arrangers and net of the original issue discount, were used to repay outstanding borrowings under the Revolving Credit Facility. The Term Loan B due 2031 is an incremental term loan under the Credit Agreement. Beginning in the first quarter of 2024, the Term Loan B due 2031 is to be paid in quarterly installments of $3,000.

106			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

7. DEBT (CONTINUED)

IMI and certain subsidiaries of IMI that represent the substantial majority of our operations in the United States, Canada and the United Kingdom guarantee all obligations under the Credit Agreement. The interest rate on borrowings under the Revolving Credit Facility varies depending on our choice of interest rate benchmark and currency options, plus an applicable margin, which varies based on our consolidated leverage ratio. The Term Loan A bears interest at the SOFR plus a credit spread adjustment of 0.1% plus 1.75%. Due to the discontinuance of the LIBOR reference rate on June 30, 2023, we transitioned the Term Loan B due 2026 from an interest rate of LIBOR plus 1.75% to a synthetic LIBOR rate plus 1.75%, effective July 1, 2023. The Term Loan B due 2031 bears interest at the SOFR plus 2.25%. Additionally, the Credit Agreement requires the payment of a commitment fee on the unused portion of the Revolving Credit Facility, which fee ranges from 0.2% to 0.3% based on our consolidated leverage ratio.

As of December 31, 2023, we had no outstanding borrowings under the Revolving Credit Facility and $228,125, $659,750 and $1,200,000 outstanding under the Term Loan A, the Term Loan B due 2026 and the Term Loan B due 2031, respectively. As of December 31, 2023, we had various outstanding letters of credit totaling $4,821 under the Revolving Credit Facility. The remaining amount available for borrowing under the Revolving Credit Facility as of December 31, 2023, which is based on IMI’s leverage ratio, the last 12 months' earnings before interest, taxes, depreciation and amortization and rent expense ("EBITDAR"), other adjustments as defined in the Credit Agreement and current external debt, was $2,245,179 (which amount represents the maximum availability as of such date). Available borrowings under the Revolving Credit Facility are subject to compliance with our indenture covenants as discussed below. The interest rate in effect under the Term Loan A as of December 31, 2023 and 2022 was 7.2% and 6.2%, respectively. The interest rate in effect under the Term Loan B due 2026 as of December 31, 2023 and 2022 was 5.2% and 4.8%, respectively. The interest rate in effect under the Term Loan B due 2031 as of December 31, 2023 was 7.6%

REVOLVING CREDIT FACILITY $2,250,000									TERM LOAN A $250,000									TERM LOAN B DUE 2026 $700,000									TERM LOAN B DUE 2031 $1,200,000
Outstanding borrowings $0									Aggregate outstanding principal amount $228,125									Aggregate outstanding principal amount $659,750									Aggregate outstanding principal amount $1,200,000
As of December 31, 2023									7.2% Interest rate									5.2% Interest rate									7.6% Interest rate
									As of December 31, 2023									As of December 31, 2023									As of December 31, 2023

B. VIRGINIA CREDIT AGREEMENTS

VIRGINIA 3 CREDIT AGREEMENT

On August 31, 2023, Iron Mountain Data Centers Virginia 3, LLC, a wholly-owned subsidiary of IMI, entered into a credit agreement (the "Virginia 3 Credit Agreement") in order to partially finance the construction of a data center facility in Virginia. The Virginia 3 Credit Agreement consists of a term loan facility and a letter of credit facility. We have the option to borrow, in the form of term loans, an aggregate outstanding amount not to exceed $275,000 (the "Virginia 3 Term Loans"). The Virginia 3 Term Loans bear interest at the SOFR plus 2.50%. The Virginia 3 Credit Agreement requires the payment of a commitment fee on any unused commitments at a rate of 0.75%. The Virginia 3 Credit Agreement is secured by the equity interests and assets of Iron Mountain Data Centers Virginia 3, LLC. The Virginia 3 Credit Agreement is scheduled to mature on August 31, 2026, at which point all obligations will become due. We have two one-year options that allow us to extend the maturity date beyond August 31, 2026, subject to the conditions specified in the Virginia 3 Credit Agreement. As of December 31, 2023, we have $101,218 in outstanding borrowings in Virginia 3 Term Loans with a weighted average interest rate of 6.2%.									MAXIMUM AMOUNT $275,000 OUTSTANDING BORROWINGS $101,218 6.2% Interest rate As of December 31, 2023

			IRON MOUNTAIN 2023 FORM 10-K			107

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

7. DEBT (CONTINUED)

VIRGINIA 4/5 CREDIT AGREEMENT

On October 31, 2022, Iron Mountain Data Centers Virginia 4/5 Subsidiary, LLC, a wholly-owned subsidiary of Iron Mountain Data Centers Virginia 4/5 JV, LP, entered into a credit agreement (the "Virginia 4/5 Credit Agreement") in order to finance the construction of two data center facilities in Virginia. The Virginia 4/5 Credit Agreement consists of a term loan facility and a letter of credit facility. We have the option to borrow, in the form of term loans, an aggregate outstanding amount not to exceed approximately $205,000 (the "Virginia 4/5 Term Loans"). The Virginia 4/5 Term Loans bear interest at SOFR plus a credit spread adjustment of 0.1% plus 1.625%. The Virginia 4/5 Credit Agreement requires the payment of a commitment fee on any unused commitments at a rate of 0.4875%. The Virginia 4/5 Credit Agreement is secured by the equity interests and assets of Iron Mountain Data Centers Virginia 4/5 Subsidiary, LLC. The Virginia 4/5 Credit Agreement is scheduled to mature on October 31, 2025, at which point all obligations will become due. We have two one-year options that allow us to extend the maturity date beyond October 31, 2025, subject to the conditions specified in the Virginia 4/5 Credit Agreement, including the lender's consent. As of December 31, 2023, we have $16,338 in outstanding borrowings in Virginia 4/5 Term Loans with a weighted average interest rate of 6.1%.									MAXIMUM AMOUNT $205,000 OUTSTANDING BORROWINGS $16,338 6.1% Interest rate As of December 31, 2023

C. NOTES ISSUED UNDER INDENTURES

Each series of notes shown below (i) is effectively subordinated to all of our secured indebtedness, including under the Credit Agreement, to the extent of the value of the collateral securing such indebtedness, (ii) ranks pari passu in right of payment with each other and with debt outstanding under the Credit Agreement, the senior notes shown below and other "senior debt" we incur from time to time and (iii) is structurally subordinated to all liabilities of our subsidiaries that do not guarantee such series of notes.

The key terms of our indentures are as follows:

SENIOR NOTES						AGGREGATE PRINCIPAL AMOUNT						DIRECT OBLIGOR						MATURITY DATE						CONTRACTUAL INTEREST RATE						INTEREST PAYMENTS DUE						PAR CALL DATE**(1)**
GBP Notes						£	400,000					IM UK						November 15, 2025						37/8%						May 15 and November 15						November 15, 2022
47/8% Notes due 2027						$	1,000,000					IMI						September 15, 2027						47/8%						March 15 and September 15						September 15, 2025
51/4% Notes due 2028						$	825,000					IMI						March 15, 2028						51/4%						March 15 and September 15						March 15, 2025
5% Notes due 2028						$	500,000					IMI						July 15, 2028						5%						January 15 and July 15						July 15, 2025
7% Notes due 2029						$	1,000,000					IMI						February 15, 2029						7%						February 15 and August 15						August 15, 2025
47/8% Notes due 2029						$	1,000,000					IMI						September 15, 2029						47/8%						March 15 and September 15						September 15, 2027
51/4% Notes due 2030						$	1,300,000					IMI						July 15, 2030						51/4%						January 15 and July 15						July 15, 2028
41/2% Notes						$	1,100,000					IMI						February 15, 2031						41/2%						February 15 and August 15						February 15, 2029
5% Notes due 2032						$	750,000					IMIM Services						July 15, 2032						5%						May 15 and November 15						July 15, 2027
55/8% Notes						$	600,000					IMI						July 15, 2032						55/8%						January 15 and July 15						July 15, 2029

(1)We may redeem the notes at any time, at our option, in whole or in part. Prior to the par call date, we may redeem the notes at the redemption price or make-whole premium specified in the applicable indenture, together with accrued and unpaid interest to, but excluding, the redemption date. On or after the par call date, we may redeem the notes at a price equal to 100% of the principal amount being redeemed, together with accrued and unpaid interest to, but excluding, the redemption date.

Each of the indentures for the notes provides that we must repurchase, at the option of the holders, the notes at 101% of their principal amount, plus accrued and unpaid interest, upon the occurrence of a "Change of Control", which is defined in each respective indenture. Except for required repurchases upon the occurrence of a Change of Control or in the event of certain asset sales, each as described in the respective indenture, we are not required to make sinking fund or redemption payments with respect to any of the notes.

108			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

7. DEBT (CONTINUED)

MAY 2023 OFFERING

On May 15, 2023, IMI completed a private offering of:

SERIES OF NOTES			AGGREGATE PRINCIPAL AMOUNT
7% Notes due 2029			$	1,000,000

The 7% Notes due 2029 were issued at 100% of par. The total net proceeds of approximately $990,000 from the issuance of the 7% Notes due 2029, after deducting the initial purchasers' commissions, were used to repay outstanding borrowings under the Revolving Credit Facility.

D. AUSTRALIAN DOLLAR TERM LOAN

Iron Mountain Australia Group Pty, Ltd., a wholly-owned subsidiary of IMI, has an AUD term loan with an original principal balance of 350,000 Australian dollars ("AUD Term Loan"). All indebtedness associated with the AUD Term Loan was issued at 99% of par. Principal payments on the AUD Term Loan are to be paid in quarterly installments in an aggregate amount of 7,695 Australian dollars per year. The AUD Term Loan bears interest at BBSY (an Australian benchmark variable interest rate) plus 3.625%. The AUD Term Loan is guaranteed by Iron Mountain Australia Group Pty, Ltd. and certain other Australian subsidiaries (the "Australia Group Guarantors") and by the guarantors of the Credit Agreement. The AUD Term Loan is secured by the capital stock and assets of the Australia Group Guarantors and by the Credit Agreement Collateral. The AUD Term Loan is scheduled to mature on September 30, 2026, at which point all obligations become due.

As of December 31, 2023, we had 292,422 Australian dollars ($199,195 based upon the exchange rate between the United States dollar and the Australian dollar as of December 31, 2023) outstanding on the AUD Term Loan. As of December 31, 2022, we had 300,117 Australian dollars ($204,623 based upon the exchange rate between the United States dollar and the Australian dollar as of December 31, 2022) outstanding on the AUD Term Loan. The interest rate in effect under the AUD Term Loan was 8.0% and 6.9% as of December 31, 2023 and 2022, respectively.									OUTSTANDING BORROWINGS AU$292,422
						8.0% Interest rate
						As of December 31, 2023

E. UK BILATERAL REVOLVING CREDIT FACILITY

IM UK and Iron Mountain (UK) Data Centre Limited, wholly owned subsidiaries of IMI (collectively, the "UK Borrowers"), have a British pounds sterling Revolving Credit Facility (the "UK Bilateral Revolving Credit Facility"). The maximum amount permitted to be borrowed under the UK Bilateral Revolving Credit Facility is 140,000 British pounds sterling. We have the option to request additional commitments of up to 125,000 British pounds sterling, subject to conditions specified in the UK Bilateral Revolving Credit Facility. IMI and subsidiaries of IMI that represent the substantial majority of our operations in the United States and the United Kingdom guarantee all obligations under the UK Bilateral Revolving Credit Facility. The UK Bilateral Revolving Credit Facility is secured by certain properties in the United Kingdom. The UK Bilateral Revolving Credit Facility bears interest at the Sterling Overnight Index Average plus 2.0%. On September 19, 2023, the UK Borrowers amended the UK Bilateral Revolving Credit Facility to extend the maturity date from September 24, 2024 to September 24, 2025. The UK Bilateral Revolving Credit Facility was fully drawn as of December 31, 2023. The interest rate in effect under the UK Bilateral Revolving Credit Facility was 7.3% and 5.5% as of December 31, 2023 and 2022, respectively.									MAXIMUM AMOUNT £140,000 OPTIONAL ADDITIONAL COMMITMENTS £125,000 7.3% Interest rate As of December 31, 2023

			IRON MOUNTAIN 2023 FORM 10-K			109

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

7. DEBT (CONTINUED)

F. ACCOUNTS RECEIVABLE SECURITIZATION PROGRAM

We participate in an accounts receivable securitization program (the "Accounts Receivable Securitization Program") involving several of our wholly-owned subsidiaries and certain financial institutions. Under the Accounts Receivable Securitization Program, certain of our subsidiaries sell substantially all of their United States accounts receivable balances to our wholly-owned special purpose entities, Iron Mountain Receivables QRS, LLC and Iron Mountain Receivables TRS, LLC (the "Accounts Receivable Securitization Special Purpose Subsidiaries"). The Accounts Receivable Securitization Special Purpose Subsidiaries use the accounts receivable balances to collateralize loans obtained from certain financial institutions. The Accounts Receivable Securitization Special Purpose Subsidiaries are consolidated subsidiaries of IMI. The Accounts Receivable Securitization Program is accounted for as a collateralized financing activity, rather than a sale of assets, and therefore: (i) accounts receivable balances pledged as collateral are presented as assets and borrowings are presented as liabilities on our Consolidated Balance Sheets, (ii) our Consolidated Statements of Operations reflect the associated charges for bad debt expense related to pledged accounts receivable (a component of selling, general and administrative expenses) and reductions to revenue due to billing and service related credit memos issued to customers and related reserves, as well as interest expense associated with the collateralized borrowings and (iii) receipts from customers related to the underlying accounts receivable are reflected as operating cash flows and borrowings and repayments under the collateralized loans are reflected as financing cash flows within our Consolidated Statements of Cash Flows. IMIM retains the responsibility of servicing the accounts receivable balances pledged as collateral for the Accounts Receivable Securitization Program and IMI provides a performance guaranty. The maximum availability allowed is limited by eligible accounts receivable, as defined under the terms of the Accounts Receivable Securitization Program. The Accounts Receivable Securitization Program is secured by a substantial majority of our net receivables in the United States.

On June 8, 2023, we amended the Accounts Receivable Securitization Program to increase the maximum borrowing capacity from $325,000 to $360,000. As of December 31, 2023 and 2022, the amount outstanding under the Accounts Receivable Securitization Program was $358,500 and $314,700, respectively. The interest rate in effect under the Accounts Receivable Securitization Program was 6.4% and 5.4% as of December 31, 2023 and 2022, respectively. Commitment fees at a rate of 35 basis points are charged on amounts made available but not borrowed under the Accounts Receivable Securitization Program.									MAXIMUM AMOUNT $360,000
						OUTSTANDING BORROWINGS $358,500 6.4% Interest rate As of December 31, 2023

G. CASH POOLING

Certain of our subsidiaries participate in cash pooling arrangements (the "Cash Pools") to help manage global liquidity requirements. We utilize the following Cash Pools: (i) two Cash Pools with Bank Mendes Gans, an independently operated wholly-owned subsidiary of ING Group, one of which we use to manage global liquidity requirements for our qualified REIT subsidiaries ("QRSs") and the other for our taxable REIT subsidiaries ("TRSs"), (ii) two Cash Pools with JP Morgan Chase Bank, N.A. ("JPM"), one of which we use to manage liquidity requirements for our QRSs in the Asia Pacific region and the other for our TRSs in the Asia Pacific region and (iii) two Cash Pools with JPM, one of which we use to manage liquidity requirements for our QRSs in the Europe, Middle East, and Africa regions and the other for our TRSs in the Europe, Middle East, and Africa regions.

Under each of the Cash Pools, cash deposited by participating subsidiaries with certain financial institutions is pledged as security against the debit balances of other participating subsidiaries with legal rights of offset provided to the financial institutions. Therefore, such amounts are presented in our Consolidated Balance Sheets on a net basis. Each subsidiary receives interest on the cash balances held on deposit or pays interest on its debit balances based on an applicable rate as defined in the Cash Pools.

The net cash position balances as of December 31, 2023 and 2022 are reflected as Cash and cash equivalents in our Consolidated Balance Sheets.

110			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

7. DEBT (CONTINUED)

H. LETTERS OF CREDIT

As of December 31, 2023, we had outstanding letters of credit totaling $38,791, of which $4,821 reduce our borrowing capacity under the Revolving Credit Facility (as described above). The letters of credit expire at various dates between January 2024 and March 2025.

I. DEBT COVENANTS

The Credit Agreement, our bond indentures and other agreements governing our indebtedness contain certain restrictive financial and operating covenants, including covenants that restrict our ability to complete acquisitions, pay cash dividends, incur indebtedness, make investments, sell assets and take other specified corporate actions. The covenants do not contain a rating trigger. Therefore, a change in our debt rating would not trigger a default under the Credit Agreement, our bond indentures or other agreements governing our indebtedness. The Credit Agreement requires that we satisfy a net total lease adjusted leverage ratio and a fixed charge coverage ratio on a quarterly basis, and our bond indentures require that, among other things, we satisfy a leverage ratio (not lease adjusted) or a fixed charge coverage ratio (not lease adjusted), as a condition to taking actions such as paying dividends and incurring indebtedness.

The Credit Agreement uses EBITDAR-based calculations and the bond indentures use EBITDA-based calculations as the primary measures of financial performance for purposes of calculating leverage and fixed charge coverage ratios. The EBITDAR- and EBITDA-based leverage calculations include our consolidated subsidiaries, other than those we have designated as "Unrestricted Subsidiaries" as defined in the Credit Agreement and bond indentures. Generally, the Credit Agreement and the bond indentures use a trailing four fiscal quarter basis for purposes of the relevant calculations and require certain adjustments and exclusions for purposes of those calculations, which make the calculation of financial performance for purposes of those calculations under the Credit Agreement and bond indentures not directly comparable to Adjusted EBITDA as presented herein. We are in compliance with our leverage and fixed charge coverage ratios under the Credit Agreement, our bond indentures and other agreements governing our indebtedness as of December 31, 2023. Noncompliance with these leverage and fixed charge coverage ratios would have a material adverse effect on our financial condition and liquidity.

J. MATURITIES OF LONG-TERM DEBT (GROSS OF DISCOUNTS) ARE AS FOLLOWS:

YEAR						AMOUNT
2024						$	120,670
2025						1,221,903
2026						1,055,120
2027						1,238,920
2028						1,393,004
Thereafter						7,015,909
						12,045,526
Net Discounts						(10,904)
Net Deferred Financing Costs						(101,452)
Total Long-term Debt (including current portion)						$	11,933,170

			IRON MOUNTAIN 2023 FORM 10-K			111

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

8. COMMITMENTS AND CONTINGENCIES

A. PURCHASE COMMITMENTS

We have certain contractual obligations related to purchase commitments which require minimum payments as follows:

YEAR						PURCHASE COMMITMENTS**(1)**
2024						$	76,443
2025						67,533
2026						27,034
2027						110,366
2028						2,664
Thereafter						2,137
						$	286,177

(1)Purchase commitments (i) include obligations related principally to software maintenance and support services and (ii) exclude our operating and financing lease obligations (see Note 2.j.) and our deferred purchase obligations (see Note 2.p.).

In addition to the above, as of December 31, 2023, we have contractual commitments of approximately $740,000 for future construction costs associated with the expansion of our Global Data Center Business that are expected to be incurred over the next one to two years.

B. SELF-INSURED LIABILITIES

We are self-insured up to certain limits for costs associated with workers’ compensation claims, vehicle accidents, property and general business liabilities and benefits paid under employee healthcare and short-term disability programs. At December 31, 2023 and 2022, there were $42,495 and $46,663, respectively, of self-insurance accruals reflected in Accrued expenses on our Consolidated Balance Sheets. The measurement of these costs requires the consideration of historical cost experience and judgments about the present and expected levels of cost per claim. We account for these costs primarily through actuarial methods, which develop estimates of the undiscounted liability for claims incurred, including those claims incurred but not reported. These methods provide estimates of future claim costs based on claims incurred as of the balance sheet date.

C. LITIGATION—GENERAL

We are involved in litigation from time to time in the ordinary course of business, including litigation arising from damage to customer assets in our facilities caused by fires and other natural disasters. A portion of the defense and/or settlement costs associated with such litigation is covered by various commercial liability insurance policies purchased by us and, in limited cases, indemnification from third parties. Our policy is to establish reserves for loss contingencies when the losses are both probable and reasonably estimable. We record legal costs associated with loss contingencies as expenses in the period in which they are incurred. While the outcome of litigation is inherently uncertain, we do not believe any current litigation will have a material adverse effect on our consolidated financial condition, results of operations or cash flows. We have estimated a reasonably possible range for all loss contingencies and believe it is reasonably possible that we could incur aggregate losses in addition to amounts currently accrued for all matters up to an additional $19,000 over the next several years.

112			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

9. STOCKHOLDERS' EQUITY MATTERS

Our board of directors has adopted a dividend policy under which we have paid, and in the future intend to pay, quarterly cash dividends on our common stock. The amount and timing of future dividends will continue to be subject to the approval of our board of directors, in its sole discretion, and to applicable legal requirements.

In 2021, 2022 and 2023, our board of directors declared the following dividends:

DECLARATION DATE						DIVIDEND PER SHARE						RECORD DATE						TOTAL AMOUNT						PAYMENT DATE
February 24, 2021						$	0.6185					March 15, 2021						$	178,569					April 6, 2021
May 6, 2021						0.6185						June 15, 2021						179,026						July 6, 2021
August 5, 2021						0.6185						September 15, 2021						179,080						October 6, 2021
November 4, 2021						0.6185						December 15, 2021						179,132						January 6, 2022
February 24, 2022						0.6185						March 15, 2022						179,661						April 6, 2022
April 28, 2022						0.6185						June 15, 2022						179,781						July 6, 2022
August 4, 2022						0.6185						September 15, 2022						179,790						October 4, 2022
November 3, 2022						0.6185						December 15, 2022						179,866						January 5, 2023
February 23, 2023						0.6185						March 15, 2023						180,339						April 5, 2023
May 4, 2023						0.6185						June 15, 2023						180,493						July 6, 2023
August 3, 2023						0.6500						September 15, 2023						189,730						October 5, 2023
November 2, 2023						0.6500						December 15, 2023						189,886						January 4, 2024

On February 22, 2024, we declared a dividend to our stockholders of record as of March 15, 2024 of $0.65 per share, payable on April 4, 2024.

During the years ended December 31, 2023, 2022 and 2021, we declared dividends in an aggregate and per share amount, based on the weighted average number of common shares outstanding during each respective year, as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Declared distributions			$	740,448					$	719,098					$	715,807
Amount per share each distribution represents based on weighted average number of common shares outstanding			2.54						2.47						2.47

			IRON MOUNTAIN 2023 FORM 10-K			113

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

9. STOCKHOLDERS’ EQUITY MATTERS (CONTINUED)

For federal income tax purposes, distributions to our stockholders are generally treated as nonqualified ordinary dividends (potentially eligible for the lower effective tax rates available for "qualified REIT dividends"), qualified ordinary dividends or return of capital. The United States Internal Revenue Service requires historical C corporation earnings and profits to be distributed prior to any REIT distributions, which may affect the character of each distribution to our stockholders, including whether and to what extent each distribution is characterized as a qualified or nonqualified ordinary dividend. In addition, certain of our distributions qualify as capital gain distributions. For the years ended December 31, 2023, 2022 and 2021, the dividends we paid on our common shares were classified as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Nonqualified ordinary dividends			98.2		%				90.4		%				53.9		%
Qualified ordinary dividends(1)			0.8		%				—		%				13.0		%
Capital gains(2)(3)			—		%				9.6		%				21.8		%
Return of capital			1.0		%				—		%				11.3		%
			100.0		%				100.0		%				100.0		%

(1)Dividends paid during the years ended December 31, 2023 and 2021 which were classified as qualified ordinary dividends for federal income tax purposes primarily related to the distribution of historical C corporation earnings and profits during the years ended December 31, 2023 and 2021. None of the dividends paid during the year ended December 31, 2022 were classified as qualified ordinary dividends for federal income tax purposes.

(2)During the year ended December 31, 2022, the percentage of our dividends that was classified as a capital gain was primarily related to the sale of land and buildings in the United States and Canada.

(3)During the year ended December 31, 2021, the percentage of our dividends that was classified as a capital gain was primarily related to the sale of land and buildings in the United States and the United Kingdom.

10. INCOME TAXES

We have been organized and have operated as a REIT effective beginning with our taxable year that ended on December 31, 2014. As a REIT, we are generally permitted to deduct from our federal taxable income the dividends we pay to our stockholders. The income represented by such dividends is not subject to federal taxation at the entity level but is taxed, if at all, at the stockholder level. The income of our domestic TRSs, which hold our domestic operations that may not be REIT-compliant as currently operated and structured, is subject, as applicable, to federal and state corporate income tax. In addition, we and our subsidiaries continue to be subject to foreign income taxes in other jurisdictions in which we have business operations or a taxable presence, regardless of whether assets are held or operations are conducted through subsidiaries disregarded for federal income tax purposes or TRSs. We will also be subject to a separate corporate income tax on any gains recognized on the sale or disposition of any asset previously owned by a C corporation during a five-year period after the date we first owned the asset as a REIT asset that are attributable to "built-in gains" with respect to that asset on that date. We will also be subject to a built-in gains tax on our depreciation recapture recognized into income as a result of accounting method changes in connection with our acquisition activities. If we fail to remain qualified for taxation as a REIT, we will be subject to federal income tax at regular corporate income tax rates. Even if we remain qualified for taxation as a REIT, we may be subject to some federal, state, local and foreign taxes on our income and property in addition to taxes owed with respect to our TRS operations. In particular, while state income tax regimes often parallel the federal income tax regime for REITs, many states do not completely follow federal rules and some do not follow them at all.

114			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

10. INCOME TAXES (CONTINUED)

The significant components of our deferred tax assets and deferred tax liabilities as of December 31, 2023 and 2022 are presented below:

			DECEMBER 31,
			2023**(1)**						2022
Deferred Tax Assets:
Accrued liabilities and other adjustments			$	100,476					$	80,159
Net operating loss carryforwards			158,363						97,161
Valuation allowance			(103,897)						(47,514)
			154,942						129,806
Deferred Tax Liabilities:
Other assets, principally due to differences in amortization			(220,218)						(243,150)
Plant and equipment, principally due to differences in depreciation			(90,156)						(78,486)
Other			(65,909)						(52,786)
			(376,283)						(374,422)
Net deferred tax liability			$	(221,341)					$	(244,616)

(1)Prior to 2023, certain of our non-United States tax loss carryforwards were determined to have a remote possibility of realization and therefore were not reported in the table above. In connection with the implementation of the OECD (as defined below) global minimum tax initiative known as Pillar Two (as defined below), any existing deferred taxes not disclosed in our 2023 financial statements will not be available in the future to reduce tax otherwise due under Pillar Two. Accordingly, beginning in 2023, we are disclosing in the above table the tax effects of these non-United States tax loss carryforwards offset with a full valuation allowance.

The deferred tax assets and deferred tax liabilities as of December 31, 2023 and 2022 are presented below:

			DECEMBER 31,
			2023						2022
Noncurrent deferred tax assets (Included in Other, a component of Other assets, net)			$	14,069					$	18,389
Deferred income taxes			(235,410)						(263,005)

At December 31, 2023, we have federal net operating loss carryforwards of $109,624, which can be carried forward indefinitely, of which $88,728 is expected to be realized to reduce future federal taxable income. We have assets for foreign net operating losses of $133,536, with various expiration dates (and in some cases no expiration date), subject to a valuation allowance of approximately 73.8%. If actual results differ unfavorably from certain of our estimates used, we may not be able to realize all or part of our net deferred income tax assets and additional valuation allowances may be required. Although we believe our estimates are reasonable, no assurance can be given that our estimates reflected in the tax provisions and accruals will equal our actual results. These differences could have a material impact on our income tax provision and operating results in the period in which such determination is made.

			IRON MOUNTAIN 2023 FORM 10-K			115

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

10. INCOME TAXES (CONTINUED)

A rollforward of the valuation allowance is as follows:

YEAR ENDED DECEMBER 31,						BALANCE AT BEGINNING OF THE YEAR						CHARGED (CREDITED) TO EXPENSE**(2)**						OTHER INCREASES/(DECREASES)****(1)(2)						BALANCE AT END OF THE YEAR
2023						$	47,514					$	4,855					$	51,528					$	103,897
2022						51,744						(1,333)						(2,897)						47,514
2021						46,938						8,406						(3,600)						51,744

(1)Other decreases and increases in valuation allowances are primarily related to changes in foreign currency exchange rates.

(2)Prior to 2023, certain of our non-United States tax loss carryforwards were determined to have a remote possibility of realization and therefore were not reported in the table above. In connection with the implementation of the OECD global minimum tax initiative known as Pillar Two, any existing deferred taxes not disclosed in our 2023 financial statements will not be available in the future to reduce tax otherwise due under Pillar Two. Accordingly, beginning in 2023, we are disclosing in the above table the tax effects of these non-United States tax loss carryforwards offset with a full valuation allowance.

The components of net income (loss) before provision (benefit) for income taxes for the years ended December 31, 2023, 2022 and 2021 are as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
United States			$	76,012					$	449,241					$	212,460
Canada			111,331						103,826						78,780
Other Foreign			39,863						78,571						337,775
Net income (loss) before provision (benefit) for income taxes			$	227,206					$	631,638					$	629,015

The provision (benefit) for income taxes for the years ended December 31, 2023, 2022 and 2021 consist of the following components:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Federal—current			$	1,255					$	24,331					$	54,867
Federal—deferred			(18,488)						(30,581)						14,322
State—current			1,544						8,553						9,566
State—deferred			(4,630)						(3,728)						(526)
Foreign—current			72,408						92,525						83,154
Foreign—deferred			(12,146)						(21,611)						14,907
Provision (Benefit) for Income Taxes			$	39,943					$	69,489					$	176,290

116			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

10. INCOME TAXES (CONTINUED)

A reconciliation of total income tax expense and the amount computed by applying the current federal statutory tax rate of 21.0% to net income (loss) before provision (benefit) for income taxes for the years ended December 31, 2023, 2022 and 2021, respectively, is as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Computed "expected" tax provision			$	47,713					$	132,644					$	132,093
Changes in income taxes resulting from:
Tax adjustment relating to REIT			(39,299)						(82,620)						(8,203)
State taxes, net of federal tax benefit			(3,147)						4,043						8,027
Increase (decrease) in valuation allowance (net of operating losses)			4,855						(1,333)						8,406
Withholding taxes			11,658						10,600						23,654
(Reversal) reserve accrual and audit settlements, net of federal tax benefit			(6,999)						40						3,072
Change in valuation of acquisition contingencies			3,242						(19,656)						—
Foreign tax rate differential			6,876						22,227						9,856
Disallowed foreign interest, Subpart F income, and other foreign taxes			14,405						2,820						(3,437)
Other, net			639						724						2,822
Provision (Benefit) for Income Taxes			$	39,943					$	69,489					$	176,290

Our effective tax rates for the years ended December 31, 2023, 2022 and 2021 were 17.6%, 11.0% and 28.0%, respectively. Our effective tax rate is subject to variability in the future due to, among other items: (i) changes in the mix of income between our QRSs and our TRSs, as well as among the jurisdictions in which we operate, (ii) tax law changes, (iii) volatility in foreign exchange gains and losses, (iv) the timing of the establishment and reversal of tax reserves, (v) our ability to utilize net operating losses that we generate and (vi) the taxability or deductibility of significant transactions.

The primary reconciling items between the federal statutory tax rate of 21.0% and our overall effective tax rate were:

YEAR ENDED DECEMBER 31,
2023			2022			2021
The benefits derived from the dividends paid deduction of $39,299 and the differences in the tax rates to which our foreign earnings are subject of $6,876. In addition, there were gains and losses recorded in Other expense (income), net during the period, for which there was no tax impact.			The benefits derived from the dividends paid deduction of $82,620 and the differences in the tax rates to which our foreign earnings are subject of $22,227. In addition, there were gains and losses recorded in Other expense (income), net and Gain (loss) on disposal/write-down of property, plant and equipment, net during the period for which there were insignificant tax impacts.			The benefits derived from the dividends paid deduction of $8,203 which was offset by (i) the impact of differences in the tax rates at which our foreign earnings are subject to, resulting in a tax provision of $9,856, and (ii) foreign withholding taxes of $23,654, which were either paid during the year or accrued, for the deferred tax liability for the United States tax impact of undistributed earnings of foreign TRSs that are no longer intended to be permanently reinvested outside the United States.

As a REIT, we are entitled to a deduction for dividends paid, resulting in a substantial reduction of federal income tax expense. As a REIT, substantially all of our income tax expense will be incurred based on the earnings generated by our foreign subsidiaries and our domestic TRSs.

			IRON MOUNTAIN 2023 FORM 10-K			117

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

10. INCOME TAXES (CONTINUED)

During 2021, as a result of the enactment of a tax law and the closing of various acquisitions, we concluded that it is no longer our intention to reinvest our undistributed earnings of our foreign TRSs indefinitely outside the United States. As a REIT, future repatriation of incremental undistributed earnings of our foreign subsidiaries will not be subject to federal or state income tax, with the exception of foreign withholding taxes. However, such future repatriations may require distributions to our stockholders in accordance with REIT distribution rules, and any such distribution may then be taxable, as appropriate, at the stockholder level. We expect to provide for foreign withholding taxes on the current and future earnings of all of our foreign subsidiaries as the result of such reassessment.

The Organization for Economic Co-operation and Development (the "OECD"), an international association comprised of 38 countries, including the United States, has issued proposals that change long-standing tax principles, including on a global minimum tax initiative. In December 2022, the European Union member states agreed to implement the OECD’s Base Erosion and Profit Shifting 2.0 Pillar Two global corporate minimum tax rate of 15% ("Pillar Two"). The agreement affirms that all member states must adopt the directive by December 31, 2023. The rules will therefore be first applicable for periods beginning after December 31, 2023. While the United States has not yet adopted the Pillar Two rules, various other governments around the world are enacting legislation. Considering we do not have material operations in jurisdictions with tax rates lower than the Pillar Two minimum, these rules are not expected to materially impact our effective tax rate, corporate tax liabilities or cash tax liabilities. There remains uncertainty as to the final Pillar Two model rules. We will continue to monitor United States and global legislative action related to Pillar Two for potential impacts.

The evaluation of an uncertain tax position is a two-step process. The first step is a recognition process whereby we determine whether it is more likely than not that a tax position will be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The second step is a measurement process whereby a tax position that meets the more likely than not recognition threshold is calculated to determine the amount of benefit to recognize in the financial statements. The tax position is measured as the largest amount of benefit that is greater than 50% likely of being realized upon ultimate settlement.

We have elected to recognize interest and penalties associated with uncertain tax positions as a component of the provision (benefit) for income taxes in the accompanying Consolidated Statements of Operations. We recorded a decrease of $2,557 and increases of $90 and $823 for gross interest and penalties for the years ended December 31, 2023, 2022 and 2021, respectively. We had $4,183 and $6,635 accrued for the payment of interest and penalties as of December 31, 2023 and 2022, respectively.

A summary of tax years that remain subject to examination by major tax jurisdictions is as follows:

TAX YEARS						TAX JURISDICTION
See Below						United States—Federal and State
2020 to present						United Kingdom
2016 to present						Canada

The normal statute of limitations for United States federal tax purposes is three years from the date the tax return is filed; however, the statute of limitations may remain open for periods longer than three years in instances where a federal tax examination is in progress. The 2022, 2021 and 2020 tax years remain subject to examination for United States federal tax purposes as well as net operating loss carryforwards utilized in these years. The normal statute of limitations for state purposes is between three to five years. However, certain of our state statute of limitations remain open for periods longer than this when audits are in progress.

We are subject to income taxes in the United States and numerous foreign jurisdictions. We are subject to examination by various tax authorities in jurisdictions in which we have business operations or a taxable presence. We regularly assess the likelihood of additional assessments by tax authorities and provide for these matters as appropriate. As of December 31, 2023, we had $23,570 of reserves related to uncertain tax positions, of which $20,488 and $3,082 is included in other long-term liabilities and deferred income taxes, respectively, in the accompanying Consolidated Balance Sheet. As of December 31, 2022, we had $27,753 of reserves related to uncertain tax positions, of which $24,671 and $3,082 is included in other long-term liabilities and deferred income taxes, respectively, in the accompanying Consolidated Balance Sheet. Although we believe our tax estimates are appropriate, the final determination of tax audits and any related litigation could result in changes to our estimates.

118			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

10. INCOME TAXES (CONTINUED)

A rollforward of unrecognized tax benefits is as follows:

Gross tax contingencies—January 1, 2021			$	25,969
Gross additions based on tax positions related to the current year			3,893
Gross additions for tax positions of prior years			344
Gross reductions for tax positions of prior years			(536)
Lapses of statutes			(1,663)
Settlements			(235)
Gross tax contingencies—December 31, 2021			27,772
Gross additions based on tax positions related to the current year			2,271
Gross additions for tax positions of prior years			723
Gross reductions for tax positions of prior years			(1,866)
Acquired unrecognized tax benefits			1,354
Lapses of statutes			(2,501)
Gross tax contingencies—December 31, 2022			27,753
Gross additions based on tax positions related to the current year			3,511
Gross additions for tax positions of prior years			634
Gross reductions for tax positions of prior years			(5,454)
Lapses of statutes			(2,874)
Gross tax contingencies—December 31, 2023			$	23,570

The reversal of the reserves of $23,570 as of December 31, 2023 will be recorded as a reduction of our income tax provision, if sustained. We believe that it is reasonably possible that an amount up to approximately $3,722 of our unrecognized tax positions may be recognized by the end of 2024 as a result of a lapse of statute of limitations or upon closing and settling significant audits in various worldwide jurisdictions.

			IRON MOUNTAIN 2023 FORM 10-K			119

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

11. SEGMENT INFORMATION

As of December 31, 2023, our two reportable segments are described as follows:

(1)Global Records and Information Management ("Global RIM") Business includes several distinct offerings:

(i)Records Management, which stores physical records and provides information services, vital records services, courier operations, and the collection, handling and disposal of sensitive documents ("Records Management") for customers in 60 countries around the globe.

(ii)Data Management, which provides storage and rotation of backup computer media as part of corporate disaster recovery plans, including service and courier operations, server and computer backup services and related services offerings ("Data Management").

(iii)Global Digital Solutions, which develops, implements and supports comprehensive storage and information management solutions for the complete lifecycle of our customers’ information, including the management of physical records, conversion of documents to digital formats and digital storage of information.

(iv)Secure Shredding, which includes the scheduled pick-up of office records that customers accumulate in specially designed secure containers we provide and is a natural extension of our hardcopy records management operations, completing the lifecycle of a record. Through a combination of shredding facilities and mobile shredding units consisting of custom built trucks, we are able to offer secure shredding services to our customers.

(v)Entertainment Services, which help entertainment and media services clients store, safeguard and deliver physical media of all types, and provides digital content repository systems that house, distribute, and archive key media assets.

(vi)Consumer Storage, which provides on-demand, valet storage for consumers utilizing data analytics and machine learning to provide effective customer acquisition and a convenient and seamless consumer storage experience.

(2)Global Data Center Business, which provides enterprise-class data center facilities and hyperscale-ready capacity to protect mission-critical assets and ensure the continued operation of our customers’ IT infrastructure, with secure, reliable and flexible data center options.

The remaining activities of our business consist primarily of our Fine Arts and ALM businesses and other corporate items ("Corporate and Other").

(i)Fine Arts provides technical expertise in the handling, installation and storing of art.

(ii)ALM provides hyperscale and corporate IT infrastructure managers with services and solutions that enable the decommissioning, data erasure, processing and disposition or sale of IT hardware and component assets. ALM services are enabled by: secure logistics, chain of custody and complete asset traceability practices, environmentally-responsible asset processing and recycling, and data sanitization and asset refurbishment services that enable value recovery through asset remarketing. In addition, ALM also offers workplace IT asset management services including storage, configuration, deployment, device support and end-of-life disposition for employee IT devices. Our ALM services focus on protecting and eradicating customer data while maintaining strong, auditable and transparent chain of custody practices.

(iii)Corporate and Other also includes costs related to executive and staff functions, including finance, human resources and IT, which benefit the enterprise as a whole.

120			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

11. SEGMENT INFORMATION (CONTINUED)

An analysis of our business segment information and reconciliation to the accompanying Consolidated Financial Statements is as follows:

			GLOBAL RIM BUSINESS						GLOBAL DATA CENTER BUSINESS						CORPORATE AND OTHER						TOTAL CONSOLIDATED
As of and for the Year Ended December 31, 2023
Total Revenues			$	4,661,776					$	495,026					$	323,487					$	5,480,289
Storage Rental			2,834,352						474,066						62,227						3,370,645
Service			1,827,424						20,960						261,260						2,109,644
Depreciation and Amortization			470,934						158,817						146,408						776,159
Depreciation			313,956						117,738						94,156						525,850
Amortization			156,978						41,079						52,252						250,309
Adjusted EBITDA			2,027,037						215,945						(281,305)						1,961,677
Total Assets(1)			10,876,225						4,788,600						1,808,977						17,473,802
Expenditures for Segment Assets			391,889						946,791						143,390						1,482,070
Capital Expenditures			284,978						928,883						125,362						1,339,223
Cash Paid for Acquisitions, Net of Cash Acquired			24,919						(764)						17,694						41,849
Acquisitions of Customer Relationships, Customer Inducements and Contract Costs			81,992						18,672						334						100,998
As of and for the Year Ended December 31, 2022
Total Revenues			$	4,295,115					$	401,125					$	407,334					$	5,103,574
Storage Rental			2,606,721						372,208						55,094						3,034,023
Service			1,688,394						28,917						352,240						2,069,551
Depreciation and Amortization			469,419						140,028						118,148						727,595
Depreciation			308,207						103,953						66,824						478,984
Amortization			161,212						36,075						51,324						248,611
Adjusted EBITDA			1,887,589						175,622						(236,154)						1,827,057
Total Assets(1)			10,654,650						3,752,088						1,733,776						16,140,514
Expenditures for Segment Assets			303,342						650,534						803,733						1,757,609
Capital Expenditures			246,216						551,232						77,930						875,378
Cash Paid for Acquisitions, Net of Cash Acquired			(23)						78,103						725,610						803,690
Acquisitions of Customer Relationships, Customer Inducements and Contract Costs			57,149						21,199						193						78,541
As of and for the Year Ended December 31, 2021
Total Revenues			$	3,994,988					$	326,898					$	169,645					$	4,491,531
Storage Rental			2,517,208						289,592						63,319						2,870,119
Service			1,477,780						37,306						106,326						1,621,412
Depreciation and Amortization			477,713						148,023						54,686						680,422
Depreciation			320,451						93,679						50,942						465,072
Amortization			157,262						54,344						3,744						215,350
Adjusted EBITDA			1,709,525						137,349						(212,175)						1,634,699
Total Assets(1)			11,101,557						2,911,823						436,651						14,450,031
Expenditures for Segment Assets			369,749						422,274						94,875						886,898
Capital Expenditures			213,395						320,768						76,919						611,082
Cash Paid for Acquisitions, Net of Cash Acquired			97,044						88,998						17,956						203,998
Acquisitions of Customer Relationships, Customer Inducements and Contract Costs			59,310						12,508						—						71,818

(1)Excludes all intercompany receivables or payables and investment in subsidiary balances.

			IRON MOUNTAIN 2023 FORM 10-K			121

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

11. SEGMENT INFORMATION (CONTINUED)

The accounting policies of the reportable segments are the same as those described in Note 2. Adjusted EBITDA for each segment is defined as net income (loss) before interest expense, net, provision (benefit) for income taxes, depreciation and amortization (inclusive of our share of Adjusted EBITDA from our unconsolidated joint ventures), and excluding certain items we do not believe to be indicative of our core operating results, specifically:

EXCLUDED
•Acquisition and Integration Costs •Restructuring and other transformation •(Gain) loss on disposal/write-down of property, plant and equipment, net (including real estate)			•Other expense (income), net •Stock-based compensation expense

Internally, we use Adjusted EBITDA as the basis for evaluating the performance of, and allocating resources to, our operating segments.

A reconciliation of Net Income (Loss) to Adjusted EBITDA on a consolidated basis for the years ended December 31, 2023, 2022 and 2021 is as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Net Income (Loss)			$	187,263					$	562,149					$	452,725
Add/(Deduct):
Interest expense, net			585,932						488,014						417,961
Provision (benefit) for income taxes			39,943						69,489						176,290
Depreciation and amortization			776,159						727,595						680,422
Acquisition and Integration Costs			25,875						47,746						12,764
Restructuring and other transformation			175,215						41,933						206,426
(Gain) loss on disposal/write-down of property, plant and equipment, net (including real estate)			(12,825)						(93,268)						(172,041)
Other expense (income), net, excluding our share of losses (gains) from our unconsolidated joint ventures(1)			98,891						(83,268)						(205,746)
Stock-based compensation expense			73,799						56,861						61,001
Our share of Adjusted EBITDA reconciling items from our unconsolidated joint ventures			11,425						9,806						4,897
Adjusted EBITDA			$	1,961,677					$	1,827,057					$	1,634,699

(1)Includes foreign currency transaction losses (gains), net, debt extinguishment expense and other, net.

122			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

11. SEGMENT INFORMATION (CONTINUED)

Information as to our operations in different geographical areas for the years ended December 31, 2023, 2022 and 2021 is as follows:

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Revenues:
United States			$	3,507,134					$	3,262,755					$	2,713,147
United Kingdom			393,917						332,556						294,675
Canada			279,325						270,836						252,385
Australia			143,815						144,840						148,431
Remaining Countries			1,156,098						1,092,587						1,082,893
Long-lived Assets:
United States			$	9,492,911					$	8,925,643					$	7,867,841
United Kingdom			1,315,715						1,062,641						914,732
Canada			498,511						514,777						562,911
Australia			484,005						490,172						528,703
Remaining Countries			3,947,115						3,600,136						3,134,577

Information as to our revenues by product and service lines by segment for the years ended December 31, 2023, 2022 and 2021 is as follows:

			GLOBAL RIM BUSINESS						GLOBAL DATA CENTER BUSINESS						CORPORATE AND OTHER						TOTAL CONSOLIDATED
For the Year Ended December 31, 2023
Records Management(1)			$	3,625,264					$	—					$	146,389					$	3,771,653
Data Management(1)			520,194						—						—						520,194
Information Destruction(1)(2)(3)			516,318						—						177,098						693,416
Data Center(1)			—						495,026						—						495,026
For the Year Ended December 31, 2022
Records Management(1)			$	3,287,237					$	—					$	137,845					$	3,425,082
Data Management(1)			510,107						—						185						510,292
Information Destruction(1)(2)(3)			497,771						—						269,304						767,075
Data Center(1)			—						401,125						—						401,125
For the Year Ended December 31, 2021
Records Management(1)			$	3,074,605					$	—					$	125,571					$	3,200,176
Data Management(1)			529,416						—						—						529,416
Information Destruction(1)(2)(3)			390,967						—						44,074						435,041
Data Center(1)			—						326,898						—						326,898

(1)Each of these offerings has a component of revenue that is storage rental related and a component that is service related, except for information destruction, which does not have a storage rental component.

(2)Information destruction revenue for our Global RIM Business includes secure shredding services.

(3)Information destruction revenue for Corporate and Other includes product revenue from our ALM business.

			IRON MOUNTAIN 2023 FORM 10-K			123

Table of Contents

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

12. RELATED PARTY TRANSACTIONS

In October 2020, in connection with the formation of the Frankfurt JV, we entered into agreements whereby we earn various fees, including (i) special project revenue and (ii) property management and construction and development fees for services we are providing to the Frankfurt JV (the "Frankfurt JV Agreements").

In March 2019, in connection with the formation of the MakeSpace JV, we entered into a storage and service agreement with the MakeSpace JV to provide certain storage and related services to the MakeSpace JV (the "MakeSpace Agreement"). In February 2022, in connection with the formation of the Clutter JV, we terminated the MakeSpace Agreement and entered into a storage and service agreement with the Clutter JV to provide certain storage and related services to the Clutter JV (the "Clutter Agreement"). On June 29, 2023, we completed the Clutter Acquisition and terminated the Clutter Agreement.

Revenue recognized in the accompanying Consolidated Statements of Operations under these agreements for the years ended December 31, 2023, 2022 and 2021 is as follows (approximately):

			YEAR ENDED DECEMBER 31,
			2023						2022						2021
Frankfurt JV Agreements(1)			$	1,800					$	15,000					$	19,600
MakeSpace Agreement and Clutter Agreement(2)			13,000						28,500						34,700

(1)Revenue associated with the Frankfurt JV Agreements is presented as a component of our Global Data Center Business segment.

(2)Revenue associated with the MakeSpace Agreement and the Clutter Agreement is presented as a component of our Global RIM Business segment.

During the years ended December 31, 2023, 2022 and 2021, the Company had no other related party transactions.

13. RESTRUCTURING AND OTHER TRANSFORMATION

PROJECT MATTERHORN

In September 2022, we announced Project Matterhorn. Project Matterhorn investments focus on transforming our operating model to a global operating model. Project Matterhorn focuses on the formation of a solution-based sales approach that is designed to allow us to optimize our shared services and best practices to better serve our customers' needs. We are investing to accelerate growth and to capture a greater share of the large, global addressable markets in which we operate. We expect to incur approximately $150,000 in costs annually related to Project Matterhorn from 2023 through 2025. Costs are comprised of (1) restructuring costs, which include (i) site consolidation and other related exit costs, (ii) employee severance costs and (iii) certain professional fees associated with these activities and (2) other transformation costs, which include professional fees such as project management costs and costs for third party consultants who are assisting in the enablement our growth initiatives.

Restructuring and other transformation related to Project Matterhorn included in the accompanying Consolidated Statements of Operations for the years ended December 31, 2023 and 2022 and from the inception of Project Matterhorn through December 31, 2023 is as follows:

			YEAR ENDED DECEMBER 31, 2023			YEAR ENDED DECEMBER 31, 2022			FROM INCEPTION THROUGH DECEMBER 31, 2023
Restructuring			$	57,319		$	13,292		$	70,611
Other transformation			117,896			28,641			146,537
Restructuring and other transformation			$	175,215		$	41,933		$	217,148

There were no Restructuring and other transformation costs related to Project Matterhorn for the year ended December 31, 2021.

124			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

13. RESTRUCTURING AND OTHER TRANSFORMATION (CONTINUED)

Restructuring costs for Project Matterhorn, included as a component of Restructuring and other transformation in the accompanying Consolidated Statements of Operations, by segment, for the years ended December 31, 2023 and 2022 and from the inception of Project Matterhorn through December 31, 2023 are as follows:

			YEAR ENDED DECEMBER 31, 2023			YEAR ENDED DECEMBER 31, 2022			FROM INCEPTION THROUGH DECEMBER 31, 2023
Global RIM Business			$	46,722		$	13,083		$	59,805
Global Data Center Business			520			—			520
Corporate and Other			10,077			209			10,286
Total restructuring costs			$	57,319		$	13,292		$	70,611

Other transformation costs for Project Matterhorn, included as a component of Restructuring and other transformation in the accompanying Consolidated Statements of Operations, by segment, for the years ended December 31, 2023 and 2022 and from the inception of Project Matterhorn through December 31, 2023 are as follows:

			YEAR ENDED DECEMBER 31, 2023			YEAR ENDED DECEMBER 31, 2022			FROM INCEPTION THROUGH DECEMBER 31, 2023
Global RIM Business			$	28,369		$	3,901		$	32,270
Global Data Center Business			4,964			58			5,022
Corporate and Other			84,563			24,682			109,245
Total other transformation costs			$	117,896		$	28,641		$	146,537

A rollforward of the accrued restructuring costs and accrued other transformation costs, which are included as components of Accrued expenses and other current liabilities in our Consolidated Balance Sheets for December 31, 2022 through December 31, 2023 is as follows:

						RESTRUCTURING						OTHER TRANSFORMATION						TOTAL RESTRUCTURING AND OTHER TRANSFORMATION
Balance as of December 31, 2022						$	1,058					$	7,029					$	8,087
Amounts accrued						57,319						117,895						175,214
Payments						(47,646)						(100,070)						(147,716)
Balance as of December 31, 2023						$	10,731					$	24,854					$	35,585

PROJECT SUMMIT

In October 2019, we announced Project Summit, our global program designed to better position us for future growth and achievement of our strategic objectives. We expanded Project Summit during the first quarter of 2020 to include additional opportunities to streamline our business and operations, as well as accelerated the timing of certain opportunities previously identified. As of December 31, 2021, we completed Project Summit.

The implementation of Project Summit resulted in total restructuring costs of approximately $450,000 that primarily consisted of: (i) employee severance costs, (ii) internal costs associated with the development and implementation of Project Summit initiatives, (iii) professional fees, primarily related to third party consultants who assisted with the design and execution of various initiatives as well as project management activities and (iv) system implementation and data conversion costs.

			IRON MOUNTAIN 2023 FORM 10-K			125

Part IV

IRON MOUNTAIN INCORPORATED

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (CONTINUED)

DECEMBER 31, 2023

(In thousands, except share and per share data)

13. RESTRUCTURING AND OTHER TRANSFORMATION (CONTINUED)

Restructuring costs for Project Summit, included as a component of Restructuring and other transformation in the accompanying Consolidated Statement of Operations, for the year ended December 31, 2021 and from the inception of Project Summit through December 31, 2021, are as follows:

						YEAR ENDED DECEMBER 31, 2021						FROM INCEPTION OF PROJECT SUMMIT THROUGH DECEMBER 31, 2021
Employee severance						$	22,809					$	91,008
Professional fees and other						183,617						358,411
Total restructuring costs						$	206,426					$	449,419

As Project Summit was completed as of December 31, 2021, there were no restructuring costs for Project Summit for the years ended December 31, 2023 and 2022.

Restructuring costs for Project Summit included in the accompanying Consolidated Statement of Operations by segment for the year ended December 31, 2021 and from the inception of Project Summit through December 31, 2021 are as follows:

						YEAR ENDED DECEMBER 31, 2021						FROM INCEPTION OF PROJECT SUMMIT THROUGH DECEMBER 31, 2021
Global RIM Business						$	59,033					$	148,073
Global Data Center Business						3,062						5,000
Corporate and Other						144,331						296,346
Total restructuring costs						$	206,426					$	449,419

126			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION

DECEMBER 31, 2023

(Dollars in thousands)

Schedule III - Schedule of Real Estate and Accumulated Depreciation ("Schedule III") reflects the cost and associated accumulated depreciation for the real estate facilities that are owned. The gross cost included in Schedule III includes the cost for land, land improvements, buildings, building improvements and racking. Schedule III does not reflect the 1,145 leased facilities in our real estate portfolio. In addition, Schedule III does not include any value for financing leases for property that is classified as land, buildings and building improvements in our consolidated financial statements.

The following table presents a reconciliation of the gross amount of real estate assets, as presented in Schedule III below, to the sum of the historical book value of land, buildings and building improvements, racking and construction in progress as disclosed in Note 2.i. to Notes to Consolidated Financial Statements as of December 31, 2023:

Gross Amount of Real Estate Assets, As Reported on Schedule III			$	4,964,366
Add (Deduct) Reconciling Items:
Book value of racking included in leased facilities(1)			1,507,354
Book value of financing leases(2)			618,338
Book value of construction in progress(3)			933,727
Book value of other			9,062
Total Reconciling Items			3,068,481
Gross Amount of Real Estate Assets, As Disclosed in Note 2.i.			$	8,032,847

(1)Represents the gross book value of racking installed in our 1,145 leased facilities, which is included in historical book value of racking in Note 2.i., but excluded from Schedule III.

(2)Represents the gross book value of buildings and building improvements that are subject to financing leases, which are included in the historical book value of building and building improvements in Note 2.i., but excluded from Schedule III.

(3)Represents the gross book value of non-real estate assets that are included in the historical book value of construction in progress assets in Note 2.i. The historical book value of real estate assets associated with owned buildings that were related to construction in progress as of December 31, 2023 is included in Schedule III.

The following table presents a reconciliation of the accumulated depreciation of real estate assets, as presented in Schedule III below, to the total accumulated depreciation for all property, plant and equipment presented on our Consolidated Balance Sheet as of December 31, 2023:

Accumulated Depreciation of Real Estate Assets, As Reported on Schedule III			$	1,305,461
Add (Deduct) Reconciling Items:
Accumulated Depreciation - non-real estate assets(1)			1,454,161
Accumulated Depreciation - racking in leased facilities(2)			1,129,751
Accumulated Depreciation - financing leases(3)			150,952
Accumulated Depreciation - other			18,795
Total Reconciling Items			2,753,659
Accumulated Depreciation, As Reported on Consolidated Balance Sheet			$	4,059,120

(1)Represents the accumulated depreciation of non-real estate assets that is included in the total accumulated depreciation of property, plant and equipment on our Consolidated Balance Sheet, but excluded from Schedule III as the assets to which this accumulated depreciation relates are not considered real estate assets associated with owned buildings.

(2)Represents the accumulated depreciation of racking as of December 31, 2023 installed in our 1,145 leased facilities, which is included in total accumulated depreciation of property, plant and equipment on our Consolidated Balance Sheet, but excluded from Schedule III, as disclosed in Footnote 1 to Schedule III.

(3)Represents the accumulated depreciation of buildings and building improvements as of December 31, 2023 that are subject to financing leases, which is included in the total accumulated depreciation of property, plant and equipment on our Consolidated Balance Sheet, but excluded from Schedule III, as disclosed in Footnote 1 to Schedule III.

			IRON MOUNTAIN 2023 FORM 10-K			127

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
North America
United States (Including Puerto Rico)
1420 North Fiesta Blvd, Gilbert, Arizona						1						$	—					$	1,637					$	2,862					$	4,499					$	2,651					2001						Up to 40 years
4802 East Van Buren, Phoenix, Arizona						1						—						15,599						479,431						495,030						20,668						2019						Up to 40 years
615 North 48th Street, Phoenix, Arizona						1						—						423,107						163,675						586,782						91,294						2018			(5)			Up to 40 years
2955 S. 18th Place, Phoenix, Arizona						1						—						12,178						15,194						27,372						8,861						2007						Up to 40 years
4449 South 36th St, Phoenix, Arizona						1						—						7,305						1,192						8,497						5,697						2012						Up to 40 years
8521 E. Princess Drive, Scottsdale, Arizona						1						—						87,865						5,088						92,953						25,437						2018			(5)			Up to 40 years
600 Burning Tree Rd, Fullerton, California						1						—						4,762						3,211						7,973						3,455						2002						Up to 40 years
21063 Forbes St, Hayward, California						1						—						13,407						641						14,048						3,688						2019			(10)			Up to 40 years
1025 North Highland Ave, Los Angeles, California						1						—						10,168						28,774						38,942						18,910						1988						Up to 40 years
1010 - 1006 North Mansfield, Los Angeles, California						1						—						749						261						1,010						185						2014						Up to 40 years
1350 West Grand Ave, Oakland, California						1						—						15,172						7,668						22,840						16,673						1997						Up to 40 years
1760 North Saint Thomas Circle, Orange, California						1						—						4,576						906						5,482						2,345						2002						Up to 40 years
1915 South Grand Ave, Santa Ana, California						1						—						3,420						1,850						5,270						2,313						2001						Up to 40 years
2680 Sequoia Dr, South Gate, California						1						—						6,329						3,339						9,668						4,746						2002						Up to 40 years
336 Oyster Point Blvd, South San Francisco, California						1						—						15,100						336						15,436						3,171						2019			(10)			Up to 40 years
3576 N. Moline, Aurora, Colorado						1						—						1,583						4,562						6,145						2,634						2001						Up to 40 years
5151 E. 46th Ave, Denver, Colorado						1						—						6,312						787						7,099						2,401						2014						Up to 40 years
11333 E 53rd Ave, Denver, Colorado						1						—						7,403						11,133						18,536						11,693						2001						Up to 40 years
4300 Brighton Boulevard, Denver, Colorado						1						—						116,336						33,339						149,675						28,699						2017						Up to 40 years

128			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
North America (continued)
United States (Including Puerto Rico) (continued)
20 Eastern Park Rd, East Hartford, Connecticut						1						$	—					$	7,417					$	2,119					$	9,536					$	6,917					2002						Up to 40 years
Kennedy Road, Windsor, Connecticut						2						—						10,447						33,511						43,958						26,398						2001						Up to 40 years
1400 Johnson Way, New Castle, Delaware						1						—						5,686						—						5,686						355						2023			(10)			Up to 40 years
150-200 Todds Ln, Wilmington, Delaware						1						—						7,226						1,245						8,471						5,712						2002						Up to 40 years
3501 Electronics Way, West Palm Beach, Florida						1						—						4,201						15,477						19,678						9,599						2001						Up to 40 years
5319 Tulane Drive SW, Atlanta, Georgia						1						—						2,808						3,984						6,792						4,701						2002						Up to 40 years
6111 Live Oak Parkway, Norcross, Georgia						1						—						3,542						3,182						6,724						986						2017						Up to 40 years
2425 South Halsted St, Chicago, Illinois						1						—						7,470						1,861						9,331						4,993						2006						Up to 40 years
1301 S. Rockwell St, Chicago, Illinois						1						—						7,947						28,471						36,418						18,659						1999						Up to 40 years
2604 West 13th St, Chicago, Illinois						1						—						404						3,095						3,499						3,069						2001						Up to 40 years
2211 W. Pershing Rd, Chicago, Illinois						1						—						4,264						14,360						18,624						10,812						2001						Up to 40 years
2255 Pratt Blvd, Elk Grove, Illinois						1						—						1,989						4,101						6,090						2,192						2000						Up to 40 years
4175 Chandler Dr Opus No. Corp, Hanover Park, Illinois						1						—						22,048						4,592						26,640						12,343						2014						Up to 40 years
2600 Beverly Drive, Lincoln, Illinois						1						—						1,378						964						2,342						511						2015						Up to 40 years
6090 NE 14th Street, Des Moines, Iowa						1						—						622						552						1,174						550						2003						Up to 40 years
South 7th St, Louisville, Kentucky						4						—						709						15,977						16,686						7,695						Various						Up to 40 years
26 Parkway Drive (fka 133 Pleasant), Scarborough, Maine						1						—						8,337						624						8,961						4,081						2015			(10)			Up to 40 years
8928 McGaw Ct, Columbia, Maryland						1						—						2,198						6,700						8,898						4,842						1999						Up to 40 years

			IRON MOUNTAIN 2023 FORM 10-K			129

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
North America (continued)
United States (Including Puerto Rico) (continued)
120 Hampden St, Boston, Massachusetts						1						$	—					$	164					$	964					$	1,128					$	681					2002						Up to 40 years
32 George St, Boston, Massachusetts						1						—						1,820						5,558						7,378						6,020						1991						Up to 40 years
3435 Sharps Lot Rd, Dighton, Massachusetts						1						—						1,911						881						2,792						2,268						1999						Up to 40 years
77 Constitution Boulevard, Franklin, Massachusetts						1						—						5,413						402						5,815						1,314						2014						Up to 40 years
Bearfoot Road, Northboro, Massachusetts						2						—						55,923						16,666						72,589						47,711						Various						Up to 40 years
6601 Sterling Dr South, Sterling Heights, Michigan						1						—						1,294						1,255						2,549						1,442						2002						Up to 40 years
3140 Ryder Trail South, Earth City, Missouri						1						—						3,072						3,566						6,638						3,168						2004						Up to 40 years
Leavenworth St/18th St, Omaha, Nebraska						2						—						2,924						19,780						22,704						10,067						Various						Up to 40 years
4105 North Lamb Blvd, Las Vegas, Nevada						1						—						3,430						10,158						13,588						7,625						2002						Up to 40 years
17 Hydro Plant Rd, Milton, New Hampshire						1						—						6,179						4,662						10,841						7,979						2001						Up to 40 years
3003 Woodbridge Avenue, Edison, New Jersey						1						—						310,404						116,859						427,263						65,368						2018			(5)			Up to 40 years
811 Route 33, Freehold, New Jersey						3						—						38,697						63,577						102,274						65,272						Various						Up to 40 years
51-69 & 77-81 Court St, Newark, New Jersey						1						—						11,734						17,802						29,536						4,415						2015						Up to 40 years
560 Irvine Turner Blvd, Newark, New Jersey						1						—						9,522						6,921						16,443						2,033						2015						Up to 40 years
231 Johnson Ave, Newark, New Jersey						1						—						8,945						3,481						12,426						2,126						2015						Up to 40 years
650 Howard Avenue, Somerset, New Jersey						1						—						3,585						12,478						16,063						8,148						2006						Up to 40 years
100 Bailey Ave, Buffalo, New York						1						—						1,324						11,583						12,907						8,395						1998						Up to 40 years

130			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
North America (continued)
United States (Including Puerto Rico) (continued)
1368 County Rd 8, Farmington, New York						1						$	—					$	2,611					$	5,336					$	7,947					$	5,649					1998						Up to 40 years
County Rd 10, Linlithgo, New York						2						—						102						3,260						3,362						2,170						2001						Up to 40 years
Ulster Ave/Route 9W, Port Ewen, New York						3						—						23,137						12,650						35,787						26,531						2001						Up to 40 years
Binnewater Rd, Rosendale, New York						2						—						5,142						12,029						17,171						9,495						Various						Up to 40 years
220 Wavel St, Syracuse, New York						1						—						2,929						2,856						5,785						3,600						1997						Up to 40 years
826 Church Street, Morrisville, North Carolina						1						—						7,087						1,046						8,133						2,243						2017						Up to 40 years
1275 East 40th, Cleveland, Ohio						1						—						3,129						606						3,735						2,425						1999						Up to 40 years
7208 Euclid Avenue, Cleveland, Ohio						1						—						3,336						5,008						8,344						4,894						2001						Up to 40 years
3366 South Tech Boulevard, Miamisburg, Ohio						1						—						29,092						2,189						31,281						6,434						2018			(5)			Up to 40 years
Branchton Rd, Boyers, Pennsylvania						2						—						21,166						282,425						303,591						98,348						Various						Up to 40 years
800 Carpenters Crossings, Folcroft, Pennsylvania						1						—						2,457						1,069						3,526						2,413						2000						Up to 40 years
Las Flores Industrial Park, Rio Grande, Puerto Rico						1						—						4,185						3,834						8,019						5,466						2001						Up to 40 years
1061 Carolina Pines Road, Columbia, South Carolina						1						—						11,776						2,779						14,555						5,236						2016			(10)			Up to 40 years
2301 Prosperity Way, Florence, South Carolina						1						—						2,846						1,353						4,199						1,910						2016			(10)			Up to 40 years
Mitchell Street, Knoxville, Tennessee						2						—						718						4,650						5,368						2,858						Various						Up to 40 years
6005 Dana Way, Nashville, Tennessee						2						—						1,827						13,169						14,996						2,715						2000						Up to 40 years
Capital Parkway, Carrollton, Texas						3						—						8,299						1,584						9,883						3,335						2015			(10)			Up to 40 years
1800 Columbian Club Dr, Carrolton, Texas						1						—						19,673						2,302						21,975						11,804						2013						Up to 40 years

			IRON MOUNTAIN 2023 FORM 10-K			131

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
North America (continued)
United States (Including Puerto Rico) (continued)
1905 John Connally Dr, Carrolton, Texas						1						$	—					$	2,174					$	1,006					$	3,180					$	1,723					2000						Up to 40 years
13425 Branchview Ln, Dallas, Texas						1						—						3,518						3,864						7,382						4,730						2001						Up to 40 years
1819 S. Lamar St, Dallas, Texas						1						—						3,215						2,209						5,424						3,104						2000						Up to 40 years
2000 Robotics Place Suite B, Fort Worth, Texas						1						—						5,328						8,711						14,039						3,946						2002						Up to 40 years
1202 Ave R, Grand Prairie, Texas						1						—						8,354						2,310						10,664						6,988						2003						Up to 40 years
6203 Bingle Rd, Houston, Texas						1						—						3,188						12,475						15,663						10,145						2001						Up to 40 years
2600 Center Street, Houston, Texas						1						—						2,840						2,754						5,594						3,139						2000						Up to 40 years
5707 Chimney Rock, Houston, Texas						1						—						1,032						1,270						2,302						1,311						2002						Up to 40 years
5249 Glenmont Ave, Houston, Texas						1						—						3,467						2,838						6,305						3,482						2000						Up to 40 years
15333 Hempstead Hwy, Houston, Texas						3						—						6,327						38,821						45,148						19,998						2004						Up to 40 years
5757 Royalton Dr, Houston, Texas						1						—						1,795						1,104						2,899						1,608						2000						Up to 40 years
9601 West Tidwell, Houston, Texas						1						—						1,680						3,382						5,062						1,782						2001						Up to 40 years
7800 Westpark, Houston, Texas						1						—						6,323						1,684						8,007						2,499						2015			(10)			Up to 40 years
1665 S. 5350 West, Salt Lake City, Utah						1						—						6,239						5,271						11,510						6,624						2002						Up to 40 years
11052 Lakeridge Pkwy, Ashland, Virginia						1						—						1,709						2,036						3,745						2,371						1999						Up to 40 years
11660 Hayden Road, Manassas, Virginia						1						—						104,824						479,940						584,764						36,581						2020						Up to 40 years
3725 Thirlane Rd. N.W., Roanoke, Virginia						1						—						2,577						300						2,877						1,448						2015			(10)			Up to 40 years
22445 Randolph Dr, Sterling, Virginia						1						—						7,598						4,491						12,089						7,230						2005						Up to 40 years
307 South 140th St, Burien, Washington						1						—						2,078						2,875						4,953						2,926						1999						Up to 40 years
6600 Hardeson Rd, Everett, Washington						1						—						5,399						4,260						9,659						4,456						2002						Up to 40 years

132			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
North America (continued)
United States (Including Puerto Rico) (continued)
1201 N. 96th St, Seattle, Washington						1						$	—					$	4,496					$	2,655					$	7,151					$	4,291					2001						Up to 40 years
4330 South Grove Road, Spokane, Washington						1						—						3,906						786						4,692						1,002						2015						Up to 40 years
12021 West Bluemound Road, Wauwatosa, Wisconsin						1						—						1,307						2,143						3,450						1,832						1999						Up to 40 years
						114						$	—					$	1,656,928					$	2,146,987					$	3,803,915					$	954,710

			IRON MOUNTAIN 2023 FORM 10-K			133

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
North America (continued)
Canada
One Command Court, Bedford						1						$	—					$	3,847					$	4,720					$	8,567					$	5,124					2000						Up to 40 years
195 Summerlea Road, Brampton						1						—						5,403						6,893						12,296						7,056						2000						Up to 40 years
10 Tilbury Court, Brampton						1						—						5,007						17,976						22,983						11,162						2000						Up to 40 years
8825 Northbrook Court, Burnaby						1						—						8,091						2,366						10,457						5,566						2001						Up to 40 years
8088 Glenwood Drive, Burnaby						1						—						4,326						7,071						11,397						6,076						2005						Up to 40 years
5811 26th Street S.E., Calgary						1						—						14,658						12,623						27,281						13,517						2000						Up to 40 years
3905-101 Street, Edmonton						1						—						2,020						1,058						3,078						1,868						2000						Up to 40 years
68 Grant Timmins Drive, Kingston						1						—						3,639						611						4,250						794						2016						Up to 40 years
3005 Boul. Jean-Baptiste Deschamps, Lachine						1						—						2,751						871						3,622						1,723						2000						Up to 40 years
1655 Fleetwood, Laval						1						—						8,196						19,883						28,079						16,261						2000						Up to 40 years
4005 Richelieu, Montreal						1						—						1,800						2,633						4,433						2,265						2000						Up to 40 years
1209 Algoma Rd, Ottawa						1						—						1,059						7,595						8,654						5,105						2000						Up to 40 years
1650 Comstock Rd, Ottawa						1						—						7,478						(201)						7,277						3,290						2017						Up to 40 years
235 Edson Street, Saskatoon						1						—						829						1,667						2,496						1,138						2008						Up to 40 years
610 Sprucewood Ave, Windsor						1						—						1,243						712						1,955						997						2007						Up to 40 years
						15						$	—					$	70,347					$	86,478					$	156,825					$	81,942
						129						$	—					$	1,727,275					$	2,233,465					$	3,960,740					$	1,036,652

134			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
Europe
Gewerbeparkstr. 3, Vienna, Austria						1						$	—					$	6,542					$	12,914					$	19,456					$	7,511					2010						Up to 40 years
Stupničke Šipkovine 62, Zagreb, Croatia						1						—						1,408						1,593						3,001						540						2003						Up to 40 years
Kratitirion 9 Kokkinotrimithia Industrial District, Nicosia, Cyprus						1						—						3,136						2,782						5,918						1,222						2003						Up to 40 years
Karyatidon 1, Agios Sylas Industrial Area (3rd), Limassol, Cyprus						1						—						1,935						(75)						1,860						350						2018						Up to 40 years
G2-B, Engineering Square IDG Developer’s Area, 6th Oct City Giza, Egypt						1						—						8,984						(3,445)						5,539						351						2021			(7)			Up to 40 years
65 Egerton Road, Birmingham, England						1						—						6,980						2,329						9,309						5,689						2003						Up to 40 years
Otterham Quay Lane, Gillingham, England						9						—						7,418						3,695						11,113						6,180						2004						Up to 40 years
Kemble Industrial Park, Kemble, England						2						—						5,277						6,856						12,133						9,049						2003						Up to 40 years
Gayton Road, Kings Lynn, England						3						—						3,119						3,086						6,205						3,308						2003						Up to 40 years
17 Broadgate, Oldham, England						1						—						4,039						242						4,281						2,627						2008						Up to 40 years
Harpway Lane, Sopley, England						1						—						681						1,593						2,274						1,582						2004						Up to 40 years
Unit 1A Broadmoor Road, Swindon, England						1						—						2,636						371						3,007						1,499						2006						Up to 40 years
Jeumont-Schneider, Champagne Sur Seine, France						3						—						1,750						2,388						4,138						2,711						2003						Up to 40 years
Bat I-VII Rue de Osiers, Coignieres, France						4						—						21,318						(3,142)						18,176						6,859						2016			(4)			Up to 40 years
26 Rue de I Industrie, Fergersheim, France						1						—						1,322						12						1,334						499						2016			(4)			Up to 40 years
Bat A, B, C1, C2, C3 Rue Imperiale, Gue de Longroi, France						1						—						3,390						671						4,061						1,673						2016			(4)			Up to 40 years
Le Petit Courtin Site de Dois, Gueslin, Mingieres, France						1						—						14,141						(418)						13,723						3,718						2016			(4)			Up to 40 years
ZI des Sables, Morangis, France						1						—						12,407						19,343						31,750						21,058						2004						Up to 40 years

			IRON MOUNTAIN 2023 FORM 10-K			135

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
Europe (continued)
45 Rue de Savoie, Manissieux, Saint Priest, France						1						$	—					$	5,546					$	(183)					$	5,363					$	1,584					2016			(4)			Up to 40 years
Heinrich Lanz Alee 47, Frankfurt, Germany						1						—						80,951						104,009						184,960						7,925						2021			(8)			Up to 40 years
Gutenbergstrabe 55, Hamburg, Germany						1						—						4,022						721						4,743						1,820						2016			(4)			Up to 40 years
Brommer Weg 1, Wipshausen, Germany						1						—						3,220						2,480						5,700						3,748						2006						Up to 40 years
Warehouse and Offices 4 Springhill, Cork, Ireland						1						—						9,040						2,580						11,620						6,306						2014						Up to 40 years
17 Crag Terrace, Dublin, Ireland						1						—						2,818						892						3,710						1,679						2001						Up to 40 years
Damastown Industrial Park, Dublin, Ireland						1						—						16,034						6,992						23,026						10,918						2012						Up to 40 years
Howemoss Drive, Aberdeen, Scotland						2						—						6,970						5,588						12,558						6,402						Various						Up to 40 years
Nettlehill Road, Houston Industrial Estate, Livingston, Scotland						1						—						11,517						27,478						38,995						22,250						2001						Up to 40 years
Av Madrid s/n Poligono Industrial Matillas, Alcala de Henares, Spain						1						—						186						225						411						358						2014						Up to 40 years
Calle Bronce, 37, Chiloeches, Spain						1						—						11,011						4,322						15,333						4,695						2010						Up to 40 years
Calle del Mar Egeo, 4, 28830, San Fernando de Hanares, Madrid, Spain						1						—						93,370						45,504						138,874						376						2022			(9)			Up to 40 years
Ctra M.118 , Km.3 Parcela 3, Madrid, Spain						1						—						3,981						6,013						9,994						7,359						2001						Up to 40 years
Plot No. S10501 & S10506 Jebel Ali Free Zone Authority, United Arab Emirates						1						—						17,000						(3,746)						13,254						1,357						2021			(7)			Up to 40 years
Abanto Ciervava, Spain						1						—						1,053						(1,053)						—						—						Various						Up to 40 years
						50						$	—					$	373,202					$	252,617					$	625,819					$	153,202

136			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
Latin America
Amancio Alcorta 2396, Buenos Aires, Argentina						2						$	—					$	655					$	(333)					$	322					$	76					Various						Up to 40 years
Azara 1245, Buenos Aires, Argentina						1						—						166						(166)						—						—						1998						Up to 40 years
Spegazzini, Ezeiza, Buenos Aires, Argentina						1						—						12,773						(12,513)						260						89						2012						Up to 40 years
Av Ernest de Moraes 815, Bairro Fim do Campo, Jarinu, Brazil						1						—						12,562						(4,053)						8,509						2,567						2016			(4)			Up to 40 years
Rua Peri 80, Jundiai, Brazil						1						—						8,894						(1,692)						7,202						2,432						2016			(4)			Up to 40 years
Francisco de Souza e Melo, Rio de Janerio, Brazil						3						—						1,868						8,085						9,953						4,200						Various						Up to 40 years
Hortolandia, Sao Paulo, Brazil						1												24,078						(3,005)						21,073						5,565						2014						Up to 40 years
El Taqueral 99, Santiago, Chile						10						—						2,629						27,792						30,421						13,288						Various						Up to 40 years
Panamericana Norte 18900, Santiago, Chile						7						—						4,001						14,813						18,814						8,389						Various						Up to 40 years
Avenida Prolongacion del Colli 1104, Guadalajara, Mexico						1						—						374						1,100						1,474						1,120						2002						Up to 40 years
Privada Las Flores No. 25 (G3), Guadalajara, Mexico						1						—						905						1,604						2,509						1,299						2004						Up to 40 years
Tula KM Parque de Las, Huehuetoca, Mexico						2						—						19,937						4,628						24,565						7,754						2016			(4)			Up to 40 years
Carretera Pesqueria Km2.5(M3), Monterrey, Mexico						2						—						3,537						3,302						6,839						2,242						2004						Up to 40 years
Lote 2, Manzana A, (T2& T3), Toluca, Mexico						1						—						2,204						3,226						5,430						2,014						2002						Up to 40 years
Prolongacion de la Calle 7 (T4), Toluca, Mexico						1						—						7,544						17,572						25,116						8,833						2007						Up to 40 years
Panamericana Sur, KM 57.5, Lima, Peru						7						—						1,549						737						2,286						1,308						Various						Up to 40 years
Av. Elmer Faucett 3462, Lima, Peru						2						—						4,112						5,272						9,384						4,786						Various						Up to 40 years
Calle Los Claveles-Seccion 3, Lima, Peru						1						—						8,179						30,342						38,521						11,670						2010						Up to 40 years
						45						$	—					$	115,967					$	96,711					$	212,678					$	77,632

			IRON MOUNTAIN 2023 FORM 10-K			137

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(A)												(B)						(C)						(D)						(E)						(F)
REGION/COUNTRY/ STATE/CAMPUS ADDRESS						FACILITIES**(1)**						ENCUMBRANCES						INITIAL COST TO COMPANY**(1)**						COST CAPITALIZED SUBSEQUENT TO ACQUISITION**(1)(2)**						GROSS AMOUNT CARRIED AT CLOSE OF CURRENT PERIOD**(1)(11)**						ACCUMULATED DEPRECIATION AT CLOSE OF CURRENT PERIOD**(1)(2)(11)**						DATE OF CONSTRUCTION OR ACQUIRED**(3)**						LIFE ON WHICH DEPRECIATION IN LATEST INCOME STATEMENT IS COMPUTED
Asia
Warehouse No 4, Shanghai, China						1						$	—					$	1,530					$	636					$	2,166					$	646					2013						Up to 40 years
Jalan Karanggan Muda Raya No 59, Bogor, Indonesia						1						—						7,897						4,327						12,224						3,447						2017						Up to 40 years
Jl. Amd Projakal KM 5.5 Rt 46, Kel. Graha Indah, Kec. Balikpapan Utara, Indonesia						1						—						125						(125)						—						—						2021						Up to 40 years
1 Serangoon North Avenue 6, Singapore						1						—						58,637						61,921						120,558						21,426						2018			(6)			Up to 40 years
2 Yung Ho Road, Singapore						1						—						10,395						1,691						12,086						5,884						2016			(4)			Up to 40 years
IC1 69 Moo 2, Soi Wat Namdaeng, Bangkok, Thailand						2						—						13,226						1,749						14,975						5,917						2016			(4)			Up to 40 years
						7						$	—					$	91,810					$	70,199					$	162,009					$	37,320
Australia
8 Whitestone Drive, Austins Ferry, Australia						1						—						681						2,439						3,120						654						2012						Up to 40 years
						1						$	—					$	681					$	2,439					$	3,120					$	654
Total						232						$	—					$	2,308,935					$	2,655,431					$	4,964,366					$	1,305,461

(1)The above information only includes the real estate facilities that are owned. The gross cost includes the cost for land, land improvements, buildings, building improvements and racking. The listing does not reflect the 1,145 leased facilities in our real estate portfolio. In addition, the above information does not include any value for financing leases for property that is classified as land, buildings and building improvements in our consolidated financial statements.

(2)Amount includes cumulative impact of foreign currency translation fluctuations.

(3)Date of construction or acquired represents the date we constructed the facility or acquired the facility through purchase or acquisition.

(4)Property was acquired in connection with our acquisition of Recall Holdings Limited.

(5)Property was acquired in connection with our acquisition of IO Data Centers, LLC.

(6)Property was acquired in connection with our acquisition of Credit Suisse International and Credit Suisse AG.

(7)Property was acquired in connection with our acquisition of Information Fort, LLC.

(8)Property was acquired in connection with the Frankfurt data center acquisition.

(9)Property was acquired in connection with our acquisition of XData Properties, S.L.U.

(10)This date represents the date the categorization of the property was changed from a leased facility to an owned facility.

138			IRON MOUNTAIN 2023 FORM 10-K

Part IV

IRON MOUNTAIN INCORPORATED

SCHEDULE III—SCHEDULE OF REAL ESTATE AND ACCUMULATED DEPRECIATION (CONTINUED)

DECEMBER 31, 2023

(Dollars in thousands)

(11)The following tables present the changes in gross carrying amount of real estate owned and accumulated depreciation for the years ended December 31, 2023 and 2022:

						YEAR ENDED DECEMBER 31,
GROSS CARRYING AMOUNT OF REAL ESTATE						2023						2022
Gross amount at beginning of period						$	4,461,195					$	4,129,251
Additions during period:
Acquisitions						—						93,370
Discretionary capital projects						535,817						434,395
Foreign currency translation fluctuations						5,046						(28,295)
						540,863						499,470
Deductions during period:
Cost of real estate sold, disposed or written-down						(27,830)						(123,633)
Other adjustments(1)						(9,862)						(43,893)
						(37,692)						(167,526)
Gross amount at end of period						$	4,964,366					$	4,461,195

(1)For the years ended December 31, 2023 and 2022, this includes the cost of racking associated with the facilities sold as part of the sale-leaseback transactions.

						YEAR ENDED DECEMBER 31,
ACCUMULATED DEPRECIATION						2023						2022
Gross amount of accumulated depreciation at beginning of period						$	1,187,390					$	1,160,490
Additions during period:
Depreciation						132,423						121,428
Foreign currency translation fluctuations						3,821						(14,664)
						136,244						106,764
Deductions during period:
Amount of accumulated depreciation for real estate assets sold, disposed or written-down						(8,856)						(41,674)
Other adjustments(1)						(9,317)						(38,190)
						(18,173)						(79,864)
Gross amount of end of period						$	1,305,461					$	1,187,390

(1)For the years ended December 31, 2023 and 2022, this includes the accumulated depreciation of racking associated with the facilities sold as part of the sale-leaseback transactions.

The aggregate cost of our real estate assets for federal tax purposes at December 31, 2023 was approximately $4,841,210.