Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations

General Overview

Overview

We own, operate, and lease shared communications infrastructure. See "Item 1. Business" for a further discussion of our business, including our long-term strategy, our REIT status, certain key terms of our contracts and growth trends in the demand for data. Site rental revenues represented 87% of our 2018 consolidated net revenues. The vast majority of our site rental revenues is of a recurring nature and has been contracted for in a prior year.

Business Fundamentals and Results

The following are certain highlights of our business fundamentals and results:

•	We operate as a REIT for U.S. federal income tax purposes (see "Item 1. Business—Company Developments, REIT Status and Industry Updates—REIT Status" and note 10 to our consolidated financial statements).

•	Potential growth resulting from the increasing demand for data

◦

We expect existing and potential new tenant demand for our communications infrastructure will result from (1) new technologies, (2) increased usage of mobile entertainment, mobile internet usage, and machine-to-machine applications, (3) adoption of other emerging and embedded wireless devices (including smartphones, laptops, tablets, and other devices), (4) increasing smartphone penetration, (5) wireless carrier focus on expanding both network quality and capacity, including the use of both towers and small cells, (6) the adoption of other bandwidth-intensive applications (such as cloud services and video communications) and (7) the availability of additional spectrum.

◦	We expect U.S. wireless carriers will continue their focus on improving network quality and expanding capacity (including through 5G initiatives) by utilizing a combination of towers and small cells. We believe our product offerings of towers and small cells provide a comprehensive solution to our wireless tenants' growing communications infrastructure needs.

◦	We expect organizations will continue to increase the usage of high-bandwidth applications that will require the utilization of more fiber infrastructure and solutions such as those we provide.

◦	Within our Fiber segment, we are able to generate growth and returns for our stockholders by deploying our fiber for both small cells and fiber solutions tenants.

◦	Tenant additions on our existing communications infrastructure are achieved at a low incremental operating cost, delivering high incremental returns.

•	Substantially all of our communications infrastructure can accommodate additional tenancy, either as currently constructed or with appropriate modifications.

•	Returning cash flows provided by operations to stockholders in the form of dividends (see also "Item 1. Business—Strategy")

◦During 2018, we paid common stock dividends totaling approximately $1.8 billion. See "Item 7. MD&A—General Overview—Common Stock Dividend" for a discussion of the increase to our quarterly dividend in the fourth quarter of 2018.

◦	Investing capital efficiently to grow long-term dividends per share (see also "Item 1. Business")

•	Discretionary capital expenditures of $1.6 billion, predominately resulting from the construction of communications infrastructure and communications infrastructure improvements in order to support additional site rental revenues.

•	We expect to continue to construct and acquire new communications infrastructure based on our tenants' needs and generate attractive long-term returns by adding additional tenants over time.

•	Site rental revenues under long-term tenant contracts

◦	Initial terms of five to 15 years for site rental revenues derived from wireless tenants, with contractual escalations and multiple renewal periods at the option of the tenant of five to 10 years each.

◦	Initial terms that generally vary between three to 20 years for site rental revenues derived from our fiber solutions tenants (including from organizations with high-bandwidth and multi-location demands).

◦	Weighted-average remaining term of approximately five years, exclusive of renewals at the tenants' option, currently representing approximately $23 billion of expected future cash inflows.

•	Majority of our revenues from large wireless carriers

◦	Approximately 73% of our site rental revenues were derived from AT&T, T-Mobile, Verizon Wireless and Sprint. See also "Item 1A. Risk Factors" and note 15 to our consolidated financial statements.

•	Majority of land interests under our towers are under long-term control.

◦

Approximately 90% of our Towers site rental gross margin and more than 75% of our Towers site rental gross margin is derived from towers that reside on land that we own or control for greater than 10 and 20 years, respectively. The aforementioned percentages include towers that reside on land interests that are owned, including fee interests and perpetual easements, which represent approximately 40% of our Towers site rental gross margin.

•	Majority of our fiber assets are located in major metropolitan areas and are on public rights-of-way.

•	Minimal sustaining capital expenditure requirements

◦	Sustaining capital expenditures represented approximately 2% of net revenues.

•	Debt portfolio with long-dated maturities extended over multiple years, with the majority of such debt having a fixed rate (see "Item 7A. Quantitative and Qualitative Disclosures About Market Risk" for a further discussion of our debt)

•	During 2018, we completed several debt transactions to refinance and extend the maturities of certain of our debt. See "Item 7. MD&A—Liquidity and Capital Resources—Financing Activities" for further discussion of our debt transactions.

◦	As of December 31, 2018, after giving effect to our February 2019 Senior Notes offering and the application of the net proceeds therefrom, our outstanding debt has a weighted average interest rate of 4.0% and weighted average maturity of approximately seven years (assuming anticipated repayment dates where applicable).

◦	After giving effect to our February 2019 issuance of $600 million aggregate principal amount of 4.300% senior unsecured notes due February 2029 and $400 million aggregate principal amount of 5.200% senior unsecured notes due 2049 (collectively, "February 2019 Senior Notes") and the application of the net proceeds therefrom, 85% of our debt has fixed rate coupons.

◦	Our debt service coverage and leverage ratios are comfortably within their respective financial maintenance covenants. See "Item 7. MD&A—Liquidity and Capital Resources—Debt Covenants" for a further discussion of our debt covenants.

•	In March 2018, we issued 8 million shares of our common stock ("March 2018 Equity Financing"), and we utilized the proceeds for general corporate purposes as well as repayment of outstanding indebtedness.

•	Significant cash flows from operations

◦	Net cash provided by operating activities was $2.5 billion.

◦	In addition to the positive impact of contractual escalators, we expect to grow our core business of providing access to our communications infrastructure as a result of future anticipated additional demand for our communications infrastructure.

Common Stock Dividend

In aggregate, we paid approximately $1.8 billion in common stock dividends in 2018. During each of the first three quarters of 2018, we paid a quarterly common stock dividend of $1.05 per share, totaling approximately $1.3 billion. In October 2018, our board of directors declared a quarterly common stock cash dividend of $1.125 per share, which represents an increase of 7% from an annualized amount of $4.20 per share to an annualized amount of $4.50 per share from the quarterly common stock dividend declared during each of the first three quarters of 2018. We currently expect our anticipated common stock dividends over the next 12 months to be a cumulative amount of at least $4.50 per share, or an aggregate amount of approximately $1.9 billion. Over time, we expect to increase our dividend per share generally commensurate with our realized growth in cash flows. Any future common stock dividends are subject to declaration by our board of directors. See notes 11 and 18 to our consolidated financial statements.

Outlook Highlights

The following are certain highlights of our 2019 outlook that impact our business fundamentals described above.

•	We expect that, when compared to full year 2018, our full year 2019 site rental revenue growth will be positively impacted by higher tenant additions, as large wireless carriers and fiber solutions tenants attempt to meet the increasing demand for data. See note 4 to our consolidated financial statements.

•	We expect discretionary capital expenditures for 2019 to exceed 2018 levels with a continued increase in the construction of new small cells and fiber as a result of the anticipated returns on such discretionary investments. We also expect sustaining capital expenditures of approximately 2% of net revenues for full year 2019.

Results of Operations

The following discussion of our results of operations should be read in conjunction with "Item 1. Business," "Item 7. MD&A—Liquidity and Capital Resources" and our consolidated financial statements.

The following discussion of our results of operations is based on our consolidated financial statements prepared in accordance with generally accepted accounting principles in the U.S. ("GAAP") which require us to make estimates and judgments that affect the reported amounts (see "Item 7. MD&A—Accounting and Reporting Matters—Critical Accounting Policies and Estimates" and note 2 to our consolidated financial statements).

Our operating segments consist of (1) Towers and (2) Fiber. See note 15 to our consolidated financial statements for further discussion of our operating segments.

See "Item 7. MD&A—Accounting and Reporting Matters—Non-GAAP and Segment Financial Measures" for a discussion of our use of (1) segment site rental gross margin, (2) segment services and other gross margin, (3) segment operating profit, including their respective definitions and (4) Adjusted EBITDA, including its definition, and a reconciliation to net income.

Highlights of our results of operations for 2018, 2017 and 2016 are depicted below:

	Years Ended December 31,												Percent Change
	2018				2017				2016				2018 vs. 2017			2017 vs. 2016
	(In millions of dollars)
Site rental revenues:
Towers site rental revenues	$	3,116			$	2,900			$	2,831			7	%		2	%
Fiber site rental revenues	1,600				769				402				108	%		91	%
Total site rental revenues	4,716				3,669				3,233				29	%		13	%
Site rental gross margin:
Towers site rental gross margin(a)	2,268				2,055				1,991				10	%		3	%
Fiber site rental gross margin(a)	1,075				505				255				113	%		98	%
Services and other gross margin:
Towers services and other gross margin(a)	273				263				259				4	%		2	%
Fiber services and other gross margin(a)	5				9				19				(44	)%		(53	)%
Segment operating profit:
Towers operating profit(a)	2,431				2,224				2,157				9	%		3	%
Fiber operating profit(a)	901				425				214				112	%		99	%
Adjusted EBITDA(b)	3,141				2,482				2,228				27	%		11	%
Net income attributable to CCIC common stockholders	558				387				324				44	%		19	%

(a)	See note 15 to our consolidated financial statements for our definitions of segment site rental gross margin, segment services and other gross margin and segment operating profit.

(b)	See reconciliation of Adjusted EBITDA in "Item 7. MD&A—Accounting and Reporting Matters—Non-GAAP and Segment Financial Measures."

2018 and 2017

Total site rental revenues for 2018 grew $1.0 billion, or 29%, from 2017. This increase was predominately comprised of the factors depicted in the chart below:

($ in millions)

(a)	Includes amortization of upfront payments received from long-term tenant contracts and other deferred credits (commonly referred to as prepaid rent).

(b)	Represents initial contribution of acquisitions until the one-year anniversary of the acquisition, with the exception of.the entire contribution to growth in site rental revenues in 2018 attributable to the Lightower Acquisition, which is included within acquisitions.

Towers site rental revenues for 2018 were approximately $3.1 billion and increased by $216 million, or 7%, from approximately $2.9 billion during 2017. The increase in Towers site rental revenues was impacted by the following items, inclusive of straight-line accounting: tenant additions across our entire portfolio, renewals or extensions of tenant contracts, escalations and non-renewals of tenants contracts. Tenant additions were influenced by our tenants' ongoing efforts to improve network quality and capacity.

Fiber site rental revenues for 2018 were $1.6 billion and increased by $831 million, or 108%, from $769 million from 2017. The increase in Fiber site rental revenues was predominately impacted by the 2017 Acquisitions and the increased demand for small cells and fiber solutions. Increased demand for small cells was driven by our tenants' network strategy in an effort to provide capacity and relieve network congestion, and increased demand for fiber solutions was driven by increasing demand for data.

The increase in Towers site rental gross margin from 2017 to 2018 was related to the previously-mentioned 7% increase in Towers site rental revenues and relatively fixed costs to operate our towers. The increase in Fiber site rental gross margins was predominately related to the previously-mentioned 108% increase in Fiber site rental revenues.

Towers services and other gross margin was $273 million for 2018 and increased by $10 million, or 4%, from $263 million in 2017, which is a reflection of (1) the volume of activity from carrier network enhancements and (2) the volume and mix of services and other work. Our services and other offerings are of a variable nature as these revenues are not under long-term contracts.

Selling, general and administrative expenses for 2018 were $563 million and increased by $137 million, or 32%, from $426 million during 2017. The increase in selling, general and administrative expenses was primarily related to the growth in our Fiber business, including the Lightower Acquisition and Wilcon Acquisition.

Towers operating profit for 2018 increased by $207 million, or 9%, from 2017. Towers operating profit was primarily reflecting the growth in our Towers site rental revenues and relatively fixed costs to operate our towers.

Fiber operating profit for 2018 increased by $476 million, or 112%, from 2017. Fiber operating profit was positively impacted by the previously-mentioned Lightower Acquisition and Wilcon Acquisition and the increased demand for small cells and fiber solutions as described above.

Depreciation, amortization and accretion was approximately $1.5 billion for 2018 and increased by $286 million, or 23%, from approximately $1.2 billion during 2017. This increase predominately resulted from a corresponding increase in our gross property and equipment due to capital expenditures and acquisitions, including the Lightower Acquisition and Wilcon Acquisition as discussed above.

Interest expense and amortization of deferred financing costs were $642 million for 2018 and increased by $51 million, or 9%, from $591 million during 2017. The increase predominately resulted from the full year impact of 2017 financing activities used to partially fund our 2017 Acquisitions and the financing of our discretionary capital expenditures. See notes 3 and 8 to our consolidated financial statements.

As a result of repaying certain of our debt, in conjunction with our refinancing activities, we incurred losses of $106 million and $4 million during 2018 and 2017, respectively. For a further discussion of the debt refinancings, see note 8 to our consolidated financial statements, "Item 7. MD&A—Liquidity and Capital Resources" and "Item 7A. Quantitative and Qualitative Disclosures About Market Risk."

The provision for income taxes for 2018 and 2017 were $19 million and $26 million, respectively. For both 2018 and 2017, the effective tax rate differs from the federal statutory rate predominately due to our REIT status, including the dividends paid deduction. In addition, in 2017 the effective rate also differs from the federal statutory rate due to a non-cash tax provision of $15 million as a result of the enactment of the Tax Reform Act. See "Item 1. Business——Company Developments, REIT Status and Industry Update—REIT Status," "Item 7. MD&A—Accounting and Reporting Matters—Critical Accounting Policies and Estimates" and note 10 to our consolidated financial statements.

Net income (loss) attributable to CCIC stockholders was income of $671 million during 2018 compared to income of $445 million during 2017. The increase was predominately related to net growth in both our Towers and Fiber segments, partially offset by an increase in expenses, including (1) depreciation, amortization and accretion, (2) selling, general and administrative expenses, (3) losses on the retirement of long-term obligations, and (4) interest expense and amortization of deferred financing costs.

Adjusted EBITDA increased $659 million, or 27%, from 2017 to 2018, reflecting the growth in our site rental activities in both Towers and Fiber, including the Lightower Acquisition and the Wilcon Acquisition as discussed above.

2017 and 2016

Total site rental revenues for 2017 grew $436 million, or 13%, from 2016. This increase was predominately comprised of the factors depicted in the chart below:

($ in millions)

(a)	Includes amortization of upfront payments received from long-term tenant contracts and other deferred credits (commonly referred to as prepaid rent).

(b)	Represents the contribution from recent acquisitions until the one-year anniversary of the acquisition.

Towers site rental revenues for 2017 were approximately $2.9 billion and increased by $69 million, or 2%, from approximately $2.8 billion during 2016. The increase in Towers site rental revenues was impacted by the following items, inclusive of straight-line accounting: tenant additions across our entire portfolio, renewals or extensions of tenant contracts, escalations and non-renewals of tenant contracts. Tenant additions were influenced by our tenants' ongoing efforts to improve network quality and capacity.

Fiber site rental revenues for 2017 were $769 million and increased by $367 million, or 91%, from $402 million in 2016. The increase in Fiber site rental revenues was predominately impacted by the 2017 Acquisitions and the increased demand for small cells and fiber solutions. Increased demand for small cells was driven by our tenants' network strategy in an effort to provide capacity and relieve network congestion, and increased demand for fiber solutions was driven by increasing demand for data.

The increase in Towers site rental gross margin from 2016 to 2017 was related to the previously-mentioned 2% increase in Towers site rental revenues and relatively fixed costs to operate our towers. The increase in Fiber site rental gross margins was predominately related to the previously-mentioned 91% increase in Fiber site rental revenues.

Towers services and other gross margin was $263 million for 2017 and increased by $4 million, or 2%, from $259 million in 2016, which is a reflection of (1) the volume of activity from carrier network enhancements and (2) the volume and mix of services and other work. Our services and other offerings are of a variable nature as these revenues are not under long-term contracts.

Selling, general and administrative expenses for 2017 were $426 million and increased by $55 million, or 15%, from $371 million during 2016. The increase in selling, general and administrative expenses was primarily related to the growth in our Fiber business, including the 2017 Acquisitions.

Towers operating profit for 2017 increased by $67 million, or 3%, from 2016. Towers operating profit was primarily reflecting the growth in our Towers site rental revenues and relatively fixed costs to operate our towers.

Fiber operating profit for 2017 increased by $211 million, or 99%, from 2016 and was positively impacted by the previously-mentioned 2017 Acquisitions and the increased demand for small cells and fiber solutions as described above.

Depreciation, amortization and accretion was approximately $1.2 billion for 2017 and increased by $133 million, or 12%, from approximately $1.1 billion during 2016. This increase predominately resulted from a corresponding increase in our gross property and equipment due to capital expenditures and acquisitions, including the 2017 Acquisitions discussed above.

Interest expense and amortization of deferred financing costs were $591 million for 2016 and increased by $76 million, or 15%, from $515 million during 2016. This increase predominately resulted from a corresponding increase in our outstanding indebtedness due to the financing of our 2017 Acquisitions and our discretionary capital expenditures. See 9 to our consolidated financial statements.

As a result of repaying and redeeming certain of our debt, in conjunction with our refinancing activities, we incurred losses of $4 million and $52 million for 2017 and 2016, respectively. For a further discussion of the debt refinancings, see note 8 to our consolidated financial statements, "Item 7. MD&A—Liquidity and Capital Resources" and "Item 7A. Quantitative and Qualitative Disclosures About Market Risk."

The provisions for income taxes for 2017 and 2016 were $26 million and $17 million, respectively. For both 2017 and 2016, the effective tax rate differs from the federal statutory rate predominately due to our REIT status, including the dividends paid deduction. In addition to our REIT status, in 2017 the effective rate differs from the federal statutory rate due to a non-cash tax provision of $15 million as a result of the enactment of the Tax Reform Act. See "Item 1. Business——Company Developments, REIT Status and Industry Update—REIT Status," "Item 7. MD&A—Accounting and Reporting Matters—Critical Accounting Policies and Estimates" and note 10 to our consolidated financial statements.

Net income (loss) attributable to CCIC stockholders for 2017 was income of $445 million during 2017 compared to income of $357 million during 2016. The increase was predominately related to net growth in both our Towers and Fiber segments as well as a decrease in the losses on retirement of long-term obligations, partially offset by an increase in expenses, including (1) interest expense and amortization of deferred financing costs, (2) depreciation, amortization and accretion and (3) general and administrative expenses.

Adjusted EBITDA increased by $254 million, or 11%, from 2016 to 2017 reflecting the growth in our site rental activities in both Towers and Fiber, including the 2017 Acquisitions as discussed above.

Liquidity and Capital Resources

Overview

General. Our core business generates revenues under long-term contracts (see "Item 1. Business—Overview" and "Item 7. MD&A—General Overview—Overview") from the largest U.S. wireless carriers and fiber solutions tenants. As a leading provider of shared communications infrastructure in the U.S., our strategy is to create long-term stockholder value via a combination of (1) growing cash flows generated from our portfolio of communications infrastructure, (2) returning a meaningful portion of our cash provided by operating activities to our stockholders in the form of dividends and (3) investing capital efficiently to grow cash flows and long-term dividends per share. Our U.S. focused strategy is based, in part, on our belief that the U.S. is the most attractive market for shared communications infrastructure investment with the greatest long-term growth potential. We measure our efforts to create "long-term stockholder value" by the combined payment of dividends to stockholders and growth in our per share results. See "Item 1. Business—Strategy" for a further discussion of our strategy.

We have engaged and expect to continue to engage in discretionary investments that we believe will maximize long-term stockholder value. Our historical discretionary investments include (in no particular order): constructing communications infrastructure, acquiring communications infrastructure, acquiring land interests (which primarily relate to land assets under towers), improving and structurally enhancing our existing communications infrastructure, purchasing shares of our common stock, and purchasing, repaying or redeeming our debt. We have recently spent and expect to continue to spend a significant percentage of our discretionary investments on the construction of new small cells and fiber. We seek to fund our discretionary investments with both net cash provided by operating activities and cash available from financing capacity, such as the use of our undrawn availability from the 2016 Revolver, debt financings and issuances of equity or equity related securities, including under our 2018 ATM Program.

We seek to maintain a capital structure that we believe drives long-term stockholder value and optimizes our weighted-average cost of capital. We target a leverage ratio of approximately four to five times Adjusted EBITDA and interest coverage of Adjusted EBITDA to interest expense of approximately three times, subject to various factors such as the availability and cost of

capital and the potential long-term return on our discretionary investments. We may choose to increase or decrease our leverage or coverage from these targets for various periods of time. We have no significant contractual debt maturities until 2021 (other than principal payments on certain outstanding debt).

We operate as a REIT for U.S. federal income tax purposes. We expect to continue to pay minimal cash income taxes as a result of our REIT status and our NOLs. See "Item 1. Business—Company Developments, REIT Status and Industry Update—REIT Status," "Item 7. MD&A—General Overview" and note 10 to our consolidated financial statements.

Liquidity Position. The following is a summary of our capitalization and liquidity position as of December 31, 2018, after giving effect to our February 2019 Senior Notes offering and the application of the net proceeds therefrom. See "Item 7A. Quantitative and Qualitative Disclosures About Market Risk",notes 8 and 18 to our consolidated financial statements for additional information regarding our debt.

	(In millions of dollars)
Cash and cash equivalents	$	277
Restricted cash(a)	136
Undrawn 2016 Revolver availability(b)	4,141
Debt and other long-term obligations (current and non-current)	16,682
Total equity	12,034

(a)	Inclusive of $5 million included within long-term prepaid rent and other assets, net on our consolidated balance sheet.

(b)	Availability at any point in time is subject to certain restrictions based on the maintenance of financial covenants contained in the 2016 Credit Facility.

See "Item 7. MD&A—Liquidity and Capital Resources—Financing Activities" and "Item 7. MD&A—Liquidity and Capital Resources—Debt Covenants."

Over the next 12 months:

•

Our liquidity sources may include (1) cash on hand, (2) net cash provided by operating activities, (3) undrawn availability under our 2016 Revolver and (4) issuances of equity pursuant to our 2018 ATM Program. Our liquidity uses over the next 12 months are expected to include (1) debt service obligations of approximately $107 million (principal payments), (2) common stock dividend payments expected to be at least $4.50 per share, or an aggregate of approximately $1.9 billion (see "Item 7. MD&A—General Overview—Common Stock Dividend"), (3) 6.875% Convertible Preferred Stock dividend payments of approximately $113 million and (4) capital expenditures (expected to be greater than current levels). During the next 12 months, while our liquidity uses are expected to exceed our net cash provided by our operating activities, we expect that our liquidity sources described above should be sufficient to cover our expected uses. Historically, from time to time, we have accessed the capital markets to issue debt and equity.

•	We have no scheduled contractual debt maturities other than principal payments on amortizing debt. See "Item 7A. Quantitative and Qualitative Disclosures About Market Risk" for a tabular presentation of our debt maturities and a discussion of anticipated repayment dates.

Summary Cash Flows Information

	Years Ended December 31,
	2018				2017				2016
	(in millions of dollars)
Net increase (decrease) in cash, cash equivalents and restricted cash - continuing operations
Operating activities	$	2,502			$	2,043			$	1,787
Investing activities	(1,795		)		(10,493		)		(1,429		)
Financing activities	(733		)		8,192				(89		)
Net increase (decrease) in cash, cash equivalents and restricted cash - continuing operations	(26		)		(258		)		269

Operating Activities. The increase in net cash provided by operating activities for 2018 from 2017 was due primarily to growth in our core business, including the Lightower Acquisition and Wilcon Acquisition, offset by a net decrease from changes in working capital. The increase in net cash provided by operating activities for 2017 from 2016 was due primarily to growth in our core business, including the 2017 Acquisitions and a net benefit from changes in working capital. Changes in working capital contribute to variability in net cash provided by operating activities, largely due to the timing of advanced payments by us and advanced receipts from tenants. We expect to grow our net cash provided by operating activities in the future (exclusive of movements in working capital) if we realize expected growth in our core business.

Investing Activities. Net cash used for investing activities for 2018 decreased $8.7 billion from 2017 as a result of the 2017 Acquisitions. See note 3 to our consolidated financial statements.

Our capital expenditures have been categorized as discretionary, sustaining or integration, as described below.

•

Discretionary capital expenditures are those capital expenditures made with respect to activities which we believe exhibit sufficient potential to enhance long-term stockholder value. They consist of expansion or development of existing communications infrastructure, construction of new communications infrastructure, and, to a lesser extent, purchases of land interests (which primarily relates to land assets under towers as we seek to manage our interests in the land beneath our towers) and other capital projects. The expansion or development of existing communications infrastructure to accommodate tenant additions typically vary based on, among other factors: (1) the type of communications infrastructure, (2) the scope, volume, and mix of work performed on the communications infrastructure, (3) existing capacity prior to installation or (4) changes in structural engineering regulations and standards. Currently, construction of new communications infrastructure is predominately comprised of the construction of small cells and fiber. Our decisions regarding discretionary capital expenditures are influenced by the availability and cost of capital and expected returns on alternative uses of cash, such as payments of dividends and investments.

•	Integration capital expenditures consist of those capital expenditures made as a result of integrating acquired companies into our business.

•	Sustaining capital expenditures consist of those capital expenditures not otherwise categorized as discretionary or integration capital expenditures, such as (1) maintenance capital expenditures on our communications infrastructure assets that enable our tenants' ongoing quiet enjoyment of the communications infrastructure and (2) corporate capital expenditures.

A summary of our capital expenditures for the last three years is as follows (in millions of dollars):

(a)	Prior to January 1, 2018, integration capital expenditures were included within sustaining capital expenditures.

Capital expenditures increased from 2017 to 2018 and were primarily impacted by the construction of small cells and fiber (including certain construction projects that may take 18 to 24 months to complete) to address our tenants' growing demand for data partially offset by lower amounts of improvements to existing towers. Our sustaining capital expenditures have historically been approximately 2% of net revenues annually and were approximately 2% of net revenues in 2018. See "Item 7. MD&A—General Overview—Outlook Highlights" for a discussion of our expectations surrounding 2019 capital expenditures.

Acquisitions. See notes 3 and 6 to our consolidated financial statements for a discussion of our acquisitions during the years ended December 31, 2017 and 2016.

Financing Activities. We seek to allocate cash generated by our operations in a manner that will enhance long-term stockholder value, which may include various financing activities, such as (in no particular order) paying dividends on our common stock (currently expected to total at least $4.50 per share over the next 12 months, or an aggregate of approximately $1.9 billion, paying dividends on our 6.875% Convertible Preferred Stock (expected to total approximately $113 million over the next 12 months), purchasing our common stock, or purchasing, repaying, or redeeming our debt. See "Item 7. MD&A—Liquidity and Capital Resources—Overview," "Item 7. MD&A—General Overview—Common Stock Dividend" and notes 8, 11 and 18 to our consolidated financial statements.

In 2018, our financing activities predominately related to the following:

•	paying an aggregate of $1.8 billion in dividends on our common stock,

•	paying an aggregate of $113 million in dividends on our 6.875% Convertible Preferred Stock;

•	issuing $1.75 billion aggregate principal amount of senior unsecured notes in January 2018, the proceeds of which we used to repay (1) in full the Senior Secured Tower Revenue Notes, Series 2010-3, Class C-2020 and pay related fees and expenses and (2) a portion of the outstanding borrowings under the 2016 Revolver;

•	completing the March 2018 Equity Financing, the proceeds of which we used for general corporate purposes, including repayment of outstanding indebtedness;

•	terminating the previously outstanding 2015 ATM Program in March 2018, and in April 2018, establishing the 2018 ATM Program through which we may issue and sell shares of our common stock having an aggregate gross sales price of up to $750 million;

•	entering into an amendment to the 2016 Credit Facility in June 2018 to (1) increase our commitments under the 2016 Revolver by $750 million for total commitments of $4.25 billion and (2) extend the maturity of the 2016 Credit Facility from August 2022 to June 2023; and

•	issuing $1.0 billion aggregate principal amount of senior secured tower revenue notes in July 2018, the proceeds of which we used, together with cash on hand, to repay, in full, the Senior Secured Tower Revenue Notes, Series 2010-6, Class C-2020 and pay related fees and expenses.

In 2017, our financing activities predominately related to the following:

•	paying an aggregate of $1.5 billion in dividends on our common stock;

•	issuing $500 million aggregate principal amount of senior unsecured notes in February 2017, the proceeds of which we used to repay a portion of the borrowings under the 2016 Revolver;

•	entering into a first amendment to the 2016 Credit Facility in February 2017 to (1) incur additional term loans in an aggregate principal amount of $500 million and (2) extend the maturity of both the 2016 Credit Facility to January 2022;

•	completing an offering of 5 million shares of our common stock, which generated net proceeds of $442 million ("May 2017 Common Stock Offering"), the proceeds of which we used to partially fund the Wilcon Acquisition;

•	issuing the $350 million aggregate principal amount of senior unsecured notes in May 2017, the proceeds of which we used to (1) partially fund the Wilcon Acquisition and (2) repay a portion of the borrowings under the 2016 Revolver;

•	completing an offering of 40 million shares of common stock, which generated net proceeds of $3.8 billion ("July 2017 Common Stock Offering"), the proceeds of which we used to partially fund the Lightower Acquisition;

•	completing and offering of 2 million shares of our 6.875% Mandatory Convertible Preferred Stock, which generated net proceeds of $1.6 billion, the proceeds of which we used to partially fund the Lightower Acquisition;

•	issuing $1.7 billion aggregate principal amount of senior unsecured notes in August 2017, the proceeds of which we used to partially fund the Lightower Acquisition and pay related fees and expenses; and

•	entering into an amendment to the 2016 Credit Facility in August 2017 to (1) increase the commitments under the 2016 Revolver by $1.0 billion, for total commitments of $3.5 billion and (2) extend the maturity of both the 2016 Term Loan A and the 2016 Revolver to August 2022.

Incurrences, Purchases and Repayments of Debt. See notes 8 and 18 to our consolidated financial statements, "Item 7. MD&A—General Overview" and "Item 7. MD&A—Liquidity and Capital Resources—Overview—Liquidity Position" for further discussion of our recent issuances, purchases and repayments of debt.

Common Stock. See notes 11 and 18 to our consolidated financial statements for further information regarding our common stock as well as dividends declared and paid.

ATM Program. See note 11 to our consolidated financial statements for further information regarding our 2018 ATM Program. As of February 22, 2019, we had approximately $750 million of gross sales of common stock availability remaining on our 2018 ATM Program.

Mandatory Convertible Preferred Stock. See note 11 to our consolidated financial statements for further information regarding our 6.875% Convertible Preferred Stock as well as dividends declared and paid during 2018.

Credit Facility. See note 8 to our consolidated financial statements for further information regarding our 2016 Credit Facility. As of February 22, 2019, there was approximately $4.1 billion in availability under the 2016 Revolver.

Restricted Cash. Pursuant to the indentures governing certain of our operating companies' debt securities, all rental cash receipts of the issuers of these debt instruments and their subsidiaries are restricted and held by an indenture trustee. The restricted cash in excess of required reserve balances is subsequently released to us in accordance with the terms of the indentures. See also note 2 to our consolidated financial statements.

Contractual Cash Obligations

The following table summarizes our contractual cash obligations as of December 31, 2018, after giving effect to our February 2019 Senior Notes offering and the application of the net proceeds therefrom. These contractual cash obligations relate primarily to our outstanding borrowings or lease obligations for land interests under our towers. The debt maturities reflect contractual maturity dates and do not consider the impact of the principal payments that will commence following the anticipated repayment dates on the tower revenue notes (see footnote (b)).

	Years Ending December 31,
Contractual Obligations(a)	2019				2020				2021				2022				2023				Thereafter				Totals
	(In millions of dollars)
Debt and other long-term obligations(b)	$	107			$	142			$	1,702			$	1,087			$	5,378			$	8,390			$	16,806
Interest payments on debt and other long-term obligations(c)(d)	648				665				644				595				475				5,334				8,361
Lease obligations(e)	640				631				628				623				619				8,054				11,195
Access agreement obligations(f)	35				24				18				15				11				64				167
Total contractual obligations	$	1,430			$	1,462			$	2,992			$	2,320			$	6,483			$	21,842			$	36,529

(a)	The following items are in addition to the obligations disclosed in the above table:

•

We have a legal obligation to perform certain asset retirement activities, including requirements upon lease and easement terminations to remove communications infrastructure or remediate the land upon which our communications infrastructure resides. The cash obligations disclosed in the above table, as of December 31, 2018, are exclusive of estimated undiscounted future cash outlays for asset retirement obligations of approximately $1.1 billion. As of December 31, 2018, the net present value of these asset retirement obligations was approximately $192 million. See note 7 to our consolidated financial statements.

•	We are contractually obligated to pay or reimburse others for property taxes related to our communications infrastructure.

•	We have the option to purchase approximately 53% of our towers that are leased or subleased or operated and managed under master leases, subleases and other agreements with AT&T, Sprint and T-Mobile at the end of their respective lease terms. We have no obligation to exercise such purchase options. See note 1 to our consolidated financial statements.

•	We have legal obligations for open purchase order commitments obtained in the ordinary course of business that have not yet been fulfilled.

(b)	The impact of principal payments that will commence following the anticipated repayment dates of our tower revenue notes is not considered. The tower revenue notes have principal amounts of $300 million, $250 million, $700 million and $750 million, with anticipated repayment dates in 2022, 2023, 2025 and 2028, respectively. See note 8 to our consolidated financial statements.

(c)

If the tower revenue notes are not repaid in full by the applicable anticipated repayment dates, the applicable interest rate increases by approximately 5% per annum and monthly principal payments commence using the Excess Cash Flow (as defined in the indenture governing the applicable tower revenue notes) of the issuers of the tower revenue notes. The tower revenue notes are presented based on their contractual maturity dates ranging from 2042 to 2048 and include the impact of an assumed 5% increase in interest rate that would occur following the anticipated repayment dates but exclude the impact of monthly principal payments that would commence using Excess Cash Flow (as defined in the indenture governing the applicable tower revenue notes) of the issuers of the tower revenue notes. The full year 2018 Excess Cash Flow (as defined in the indenture governing the applicable tower revenue notes) of the issuers of the tower revenue notes was approximately $720 million. We currently expect to refinance these notes on or prior to the respective anticipated repayment dates.

(d)	Interest payments on the floating rate debt are based on estimated rates currently in effect.

(e)

Amounts relate primarily to lease obligations for the land interests on which our towers reside and are based on the assumption that payments will be made for certain renewal periods at our option that are reasonably certain to be exercised and an estimate of contingent payments based on revenues and gross margins derived from existing tenant leases. See table below summarizing remaining terms to expiration.

(f)

Amounts relate primarily to access agreement obligations for rights-of-way, franchise pole attachments and other agreements to operate our fiber assets and are based on the assumption that payments will be made for certain renewal periods at our option that are reasonably certain to be exercised and an estimate of contingent payments based on revenues and gross margins derived from existing tenant contracts.

The following chart summarizes our rights to the land interests under our towers, including renewal terms at our option, as of December 31, 2018. As of December 31, 2018, the leases for land interests under our towers had an average remaining life of approximately 35 years, weighted based on Towers site rental gross margin. See "Item 1A. Risk Factors."

(a)	Inclusive of fee interests and perpetual easements.

(b)	For the year ended December 31, 2018, without consideration of the term of the tenant contract.

Debt Covenants

The credit agreement governing the 2016 Credit Facility contains financial maintenance covenants. We are currently in compliance with these financial maintenance covenants and, based upon our current expectations, we believe we will continue to comply with these financial maintenance covenants. In addition, certain of our debt agreements also contain restrictive covenants that place restrictions on us and may limit our ability to, among other things, incur additional debt and liens, purchase our securities, make capital expenditures, dispose of assets, undertake transactions with affiliates, make other investments, pay dividends or distribute excess cash flow. See note 8 to our consolidated financial statements for further discussion of our debt covenants. See "Item 1A. Risk Factors." The following are ratios applicable to the financial maintenance covenants under the credit agreement governing our 2016 Credit Facility as of December 31, 2018.

Borrower / Issuer	Financial Maintenance Covenant(a)(b)	Covenant Level Requirement	As of December 31, 2018
CCIC	Total Net Leverage Ratio	≤ 6.50x	5.2x
CCIC	Total Senior Secured Leverage Ratio	≤ 3.50x	1.0x
CCIC	Consolidated Interest Coverage Ratio(c)	N/A	N/A

(a)	Failure to comply with the financial maintenance covenants would, absent a waiver, result in an event of default under the credit agreement governing our 2016 Credit Facility.

(b)	As defined in the credit agreement governing our 2016 Credit Facility.

(c)	Applicable solely to the extent that the senior unsecured debt rating by any two of S&P, Moody's and Fitch is lower than BBB-, Baa3 or BBB-, respectively. If applicable, the consolidated interest coverage ratio must be greater than or equal to 2.50.

Off-balance Sheet Arrangements

We have no off-balance sheet arrangements as defined in Item 303(a)(4)(ii) of Regulation S-K.

Accounting and Reporting Matters

Critical Accounting Policies and Estimates

The following is a discussion of the accounting policies and estimates in effect for 2018 that we believe (1) are most important to the portrayal of our financial condition and results of operations or (2) require our most difficult, subjective or complex judgments, often as a result of the need to make estimates about the effect of matters that are inherently uncertain. The critical accounting policies and estimates for 2018 are not intended to be a comprehensive list of our accounting policies and estimates. See note 2 to our consolidated financial statements for a summary of our significant accounting policies. In many cases, the accounting treatment of a particular transaction is specifically prescribed by GAAP. In other cases, management is required to exercise judgment in the application of accounting principles with respect to particular transactions.

Revenue Recognition. 87% of our total revenue for 2018 consists of site rental revenues, which are recognized on a ratable basis over the fixed, non-cancelable term of the relevant contract (generally ranging from five to 15 years for site rental revenues derived from wireless tenants and three to 20 years for site rental revenues derived from our fiber solutions business), regardless of whether the payments from the tenant are received in equal monthly amounts during the life of a contract. Certain of our contracts contain fixed escalation clauses (such as fixed-dollar or fixed-percentage increases) or inflation-based escalation clauses (such as those tied to the consumer price index). If the payment terms call for fixed escalations, upfront payments or rent free periods, the revenue is recognized on a straight-line basis over the fixed, non-cancelable term of the contract. When calculating our straight-line rental revenues, we consider all fixed elements of tenant contractual escalation provisions, even if such escalation provisions contain a variable element (such as an escalator tied to an inflation-based index) in addition to a minimum. To the extent we acquire below-market tenant leases for contractual interests with tenants on the acquired communications infrastructure (for example with respect to small cells and fiber), we record the fair value as deferred credits and amortize such deferred credits to site rental revenues over their estimated lease term. Since we recognize revenue on a straight-line basis, a portion of the site rental revenue in a given period represents cash collected or contractually collectible in other periods. Our assets related to straight-line site rental revenues are included in "other current assets" and "deferred site rental receivables." Amounts billed or received prior to being earned are deferred and reflected in "deferred revenues" and "other long-term liabilities." Amounts to which we have an unconditional right to payment, which are related to both satisfied or partially satisfied performance obligations, are recorded within "receivables, net" on the consolidated balance sheet.

As part of our effort to provide comprehensive communications infrastructure solutions, we also offer certain services primarily relating to our communications infrastructure, which represent13% of our total revenues for 2018. Services and other revenue consists of (1) site development services primarily relating to existing or new tenant equipment installations on our towers

and small cells, including: site acquisition, architectural and engineering, or zoning and permitting (collectively, "site development services") and (2) tenant equipment installation or subsequent augmentations (collectively, "installation services"). Upon contract commencement, we assess our services to tenants and identify performance obligations for each promise to provide a distinct service.

We may have multiple performance obligations for site development services, which primarily include: structural analysis, zoning, permitting and construction drawings. For each of the above performance obligations, services revenues are recognized at completion of the applicable performance obligation, which represents the point at which we believe we have transferred goods or services to the tenant. The revenue recognized is based on an allocation of the transaction price among the performance obligations in a respective contract based on estimated standalone selling price. We have one performance obligation for installation services, which is satisfied at the time of the respective installation or augmentation. Since performance obligations are typically satisfied prior to receiving payment from tenants, the unconditional right to payment is recorded within "receivables, net" on our consolidated balance sheet.

The vast majority of our services revenues relates to our Towers segment and generally have a duration of one year or less. See notes 2 to our consolidated financial statements.

Accounting for Acquisitions — General. As described in "Item 1. Business," the majority of our communications infrastructure has been acquired directly or indirectly from the four largest wireless carriers (or their predecessors) through transactions consummated since 1999. We evaluate each of our acquisitions to determine if it should be accounted for as a business combination or as an acquisition of assets. For our business combinations, we allocate the purchase price to the assets acquired and liabilities assumed based on their estimated fair value at the date of acquisition. Any purchase price in excess of the net fair value of the assets acquired and liabilities assumed is allocated to goodwill. See "Item 7. MD&A—Accounting and Reporting Matters—Accounting for Acquisitions—Valuation" below and note 2 to our consolidated financial statements.

The determination of the final purchase price allocation could extend over several quarters resulting in the use of preliminary estimates that are subject to adjustment until finalized. Such changes could have a significant impact on our financial statements.

Accounting for Acquisitions — Leases. With respect to business combinations that include towers that we lease and operate, such as the AT&T, T-Mobile and Sprint leased and subleased towers, we evaluate such agreements to determine treatment as capital or operating leases. The evaluation of such agreements for capital or operating lease treatment includes consideration of each of the lease classification criteria under ASC 840-10-25, namely (1) the transfer of ownership provisions, (2) the existence of bargain purchase options, (3) the length of the remaining lease term, and (4) the present value of the minimum lease payments. With respect to the AT&T Acquisition, T-Mobile Acquisition, and the Sprint towers acquired in the Global Signal Acquisition, we determined that the tower leases were capital leases and the underlying land leases were operating leases based upon the lease term criterion, after considering the fragmentation criteria applicable under ASC 840-10-25 to leases involving both land and buildings (i.e., towers). We determined that the fragmentation criteria was met, and the tower leases could be accounted for as capital leases apart from the land leases, which are accounted for as operating leases, since (1) the fair value of the land in the aforementioned business combinations was greater than 25% of the total fair value of the leased property at inception and (2) the tower lease expirations occur beyond 75% of the estimated economic life of the tower assets.

Effective January 1, 2019, we adopted new lease accounting guidance on the recognition, measurement, presentation and disclosure of leases. See note 2 to our consolidated financial statements for further information.

Accounting for Acquisitions — Valuation. As of December 31, 2018, our largest asset was property and equipment, which primarily consists of communications infrastructure, followed by goodwill and intangible assets. Our identifiable intangible assets predominately relate to the site rental contracts and tenant relationships intangible assets. See note 2 to our consolidated financial statements for further information regarding the nature and composition of the site rental contracts and tenant relationships intangible assets.

The fair value of the vast majority of our assets and liabilities is determined by using either:

(1)	discounted cash flow valuation methods (for estimating identifiable intangibles such as site rental contracts and tenant relationships and above-market and below-market leases) or

(2)	estimates of replacement costs (for tangible fixed assets such as communications infrastructure).

The purchase price allocation requires subjective estimates that, if incorrectly estimated, could be material to our consolidated financial statements, including the amount of depreciation, amortization and accretion expense. The most important estimates for measurement of tangible fixed assets are (1) the cost to replace the asset with a new asset and (2) the economic useful life after giving effect to age, quality, and condition. The most important estimates for measurement of intangible assets are (1) discount rates and (2) timing and amount of cash flows including estimates regarding tenant renewals and cancellations. The most important

estimates for measurement of above and below-market leases is the determination of (1) favorability or unfavorability to the current market terms and (2) applicable lease term, including whether renewals or extensions should be measured. With respect to business combinations that include towers that we lease and operate, such as the T-Mobile, Sprint and AT&T leased and subleased towers, we evaluate such agreements to determine treatment as capital or operating leases and identification of any bargain purchase options.

We record the fair value of obligations to perform certain asset retirement activities, including requirements, pursuant to our ground lease, easements, and leased facility agreements to remove communications infrastructure or remediate the space upon which certain of our communications infrastructure resides. In determining the fair value of these asset retirement obligations we must make several subjective and highly judgmental estimates such as those related to: (1) timing of cash flows; (2) future costs; (3) discount rates; and (4) the probability of enforcement to remove the towers or small cells or remediate the land. See note 2 to our consolidated financial statements.

Accounting for Long-Lived Assets — Useful Lives. We are required to make subjective assessments as to the useful lives of our tangible and intangible assets for purposes of determining depreciation, amortization and accretion expense that, if incorrectly estimated, could be material to our consolidated financial statements. Depreciation expense for our property and equipment is computed using the straight-line method over the estimated useful lives of our various classes of tangible assets. The substantial portion of our property and equipment represents the cost of our communications infrastructure, which is depreciated with an estimated useful life equal to the shorter of (1) 20 years or (2) the term of the lease (including optional renewals) for the land interests under the communications infrastructure.

The useful life of our intangible assets is estimated based on the period over which the intangible asset is expected to benefit us and gives consideration to the expected useful life of other assets to which the useful life may relate. We review the expected useful lives of our intangible assets on an ongoing basis and adjust if necessary. Amortization expense for intangible assets is computed using the straight-line method over the estimated useful life of each of the intangible assets. The useful life of the site rental contracts and tenant relationships intangible assets is limited by the maximum depreciable life of the communications infrastructure (20 years), as a result of the interdependency of the communications infrastructure and site rental contracts and tenant relationships. In contrast, the site rental contracts and tenant relationships are estimated to provide economic benefits for several decades because of the low rate of tenant cancellations and high rate of renewals experienced to date. Thus, while site rental contracts and tenant relationships are valued based upon the fair value of the site rental contracts and tenant relationships which includes assumptions regarding both (1) tenants' exercise of optional renewals contained in the acquired leases and (2) renewals of the acquired leases past the contractual term including exercisable options, the site rental contracts are amortized over a period not to exceed 20 years as a result of the useful life being limited by the depreciable life of the communications infrastructure.

Accounting for Long-Lived Assets — Impairment Evaluation. We review the carrying values of property and equipment, intangible assets, or other long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amounts may not be recoverable. We utilize the following dual grouping policy for purposes of determining the unit of account for testing impairment of the site rental contracts and tenant relationships:

(1)	we pool site rental contracts and tenant relationships intangible assets and property and equipment into portfolio groups; and

(2)	we separately pool site rental contracts and tenant relationships by significant tenant or by tenant grouping for individually insignificant tenants, as appropriate.

We first pool site rental contracts and tenant relationships intangible assets and property and equipment into portfolio groups for purposes of determining the unit of account for impairment testing, because we view communications infrastructure as portfolios and communications infrastructure in a given portfolio and its related tenant contracts are not largely independent of the other communications infrastructure in the portfolio. We re-evaluate the appropriateness of the pooled groups at least annually. This use of grouping is based in part on (1) our limitations regarding disposal of communications infrastructure, (2) the interdependencies of communications infrastructure portfolios, and (3) the manner in which communications infrastructure is traded in the marketplace. The vast majority of our site rental contracts and tenant relationships intangible assets and property and equipment are pooled into the U.S. owned communications infrastructure group. Secondly, and separately, we pool site rental contracts and tenant relationships by significant tenant or by tenant grouping for individually insignificant tenants, as appropriate, for purposes of determining the unit of account for impairment testing because we associate the value ascribed to site rental contracts and tenant relationships intangible assets to the underlying contracts and related tenant relationships acquired.

Our determination that an adverse event or change in circumstance has occurred that indicates that the carrying amounts may not be recoverable will generally involve (1) a deterioration in an asset's financial performance compared to historical results, (2) a shortfall in an asset's financial performance compared to forecasted results, or (3) changes affecting the utility and estimated future

demands for the asset. When considering the utility of our assets, we consider events that would meaningfully impact (1) our communications infrastructure or (2) our tenant relationships. For example, consideration would be given to events that impact (1) the structural integrity and longevity of our communications infrastructure or (2) our ability to derive benefit from our existing tenant relationships, including events such as tenant's bankruptcy or insolvency or loss of a significant tenant. During 2018, there were no events or circumstances that caused us to review the carrying value of our intangible assets or property and equipment due in part to our assets performing consistently with or better than our expectations.

If the sum of the estimated future cash flows (undiscounted) from an asset, or portfolio group, significant tenant or tenant group (for individually insignificant tenants), as applicable, is less than its carrying amount, an impairment loss may be recognized. If the carrying value were to exceed the undiscounted cash flows, measurement of an impairment loss would be based on the fair value of the asset, which is based on an estimate of discounted future cash flows. The most important estimates for such calculations of undiscounted cash flows are (1) the expected additions of new tenants and equipment on our communications infrastructure and (2) estimates regarding tenant cancellations and renewals of contracts. We could record impairments in the future if changes in long-term market conditions, expected future operating results or the utility of the assets results in changes for our impairment test calculations which negatively impact the fair value of our property and equipment and intangible assets, or if we changed our unit of account in the future.

Approximately 2% of our total towers currently have no tenants. We continue to pay operating expenses on these towers in anticipation of obtaining tenants on these towers in the future, primarily because of the individual tower site demographics. We estimate, based on current visibility, potential tenants on approximately half of these towers. To the extent we do not believe there are long-term prospects of obtaining tenants on an individual asset and all other possible avenues for recovering the carrying value has been exhausted, including sale of the asset, we appropriately reduce the carrying value of such assets to fair value.

Accounting for Goodwill — Impairment Evaluation. We test goodwill for impairment on an annual basis, regardless of whether adverse events or changes in circumstances have occurred. The annual test begins with goodwill and all intangible assets being allocated to applicable reporting units. We then perform a qualitative assessment to determine whether it is "more likely than not" that the fair value of the reporting unit is less than its carrying amount. If we conclude that it is "more likely than not" that the fair value of a reporting unit is less than its carrying amount, we would be required to perform the two-step goodwill impairment test. Otherwise, the two-step goodwill impairment test is not required. Our reporting units are the same as our operating segments (Towers and Fiber). See note 15. We performed our most recent annual goodwill impairment test as of October 1, 2018, which resulted in (1) the fair value of our reporting units substantially exceeding the carrying value and (2) no impairments.

Deferred Income Taxes. We operate as a REIT for U.S. federal income tax purposes. Our REIT taxable income is generally not subject to federal and state income taxes as a result of the deduction for dividends paid and any usage of our remaining NOLs. Accordingly, the only provision or benefit for federal income taxes for the year ended December 31, 2018 relates to TRSs. Furthermore, as a result of the deduction for dividends paid, some or all of our NOLs related to our REIT may expire without utilization. See "Item 1. Business—Company Developments, REIT Status and Industry Update—REIT Status" for a discussion of the impact of our REIT status.

Our TRSs will continue to be subject, as applicable, to federal and state income taxes and foreign taxes in the jurisdictions in which such assets and operations are located. Our ability to utilize our NOLs is dependent, in part, upon us having sufficient future earnings to utilize our NOLs before they expire. If market conditions change materially and we determine that we will be unable to generate sufficient taxable income in the future to utilize our NOLs, we would be required to record an additional valuation allowance, which would reduce our earnings. Such adjustments could cause a material effect on our results of operations for the period of the adjustment. The change in our valuation allowance has no effect on our cash flows. For a further discussion of our benefit (provision) for income taxes, see "Item 7. MD&A—Results of Operations" and note 10 to our consolidated financial statements.

Accounting Pronouncements

Recently Adopted Accounting Pronouncements. See note 2 to our consolidated financial statements.

Recent Accounting Pronouncements Not Yet Adopted. See note 2 to our consolidated financial statements.

Non-GAAP and Segment Financial Measures

In addition to the non-GAAP financial measures used herein and as discussed in note 15 to our consolidated financial statements, we also provide (1) segment site rental gross margin, (2) segment services and other gross margin, and (3) segment operating profit, which are key measures used by management to evaluate the performance of our operating segments . These segment measures are provided pursuant to GAAP requirements related to segment reporting.

We define segment site rental gross margin as segment site rental revenues less segment site rental cost of operations, which excludes stock-based compensation expense and prepaid lease purchase price adjustments recorded in consolidated site rental cost of operations. We define segment services and other gross margin as segment services and other revenues less segment services and other cost of operations, which excludes stock-based compensation expense recorded in consolidated services and other cost of operations. We define segment operating profit as segment site rental gross margin plus segment services and other gross margin, less selling, general and administrative expenses attributable to the respective segment. All of these measurements of profit or loss are exclusive of depreciation, amortization and accretion, which are shown separately.

We use earnings before interest, taxes, depreciation, amortization, and accretion, as adjusted ("Adjusted EBITDA"), which is a non-GAAP financial measure, as an indicator of consolidated financial performance. Our measure of Adjusted EBITDA may not be comparable to similarly titled measures of other companies, including companies in the communications infrastructure sector or other REITs, and is not a measure of performance calculated in accordance with GAAP. Adjusted EBITDA should not be considered in isolation or as a substitute for operating income (loss), net income (loss), net cash provided by (used for) operating, investing and financing activities or other income statement or cash flow statement data prepared in accordance with GAAP and should be considered only as a supplement to net income (loss) computed in accordance with GAAP as a measure of our performance. There are material limitations to using a measure such as Adjusted EBITDA, including the difficulty associated with comparing results among more than one company, including our competitors, and the inability to analyze certain significant items, including depreciation and interest expense, that directly affect our net income or loss. Management compensates for these limitations by considering the economic effect of the excluded expense items independently as well as in connection with their analysis of net income (loss).

We define Adjusted EBITDA as net income (loss) plus restructuring charges (credits), asset write-down charges, acquisition and integration costs, depreciation, amortization and accretion, amortization of prepaid lease purchase price adjustments, interest expense and amortization of deferred financing costs, (gains) losses on retirement of long-term obligations, net (gain) loss on interest rate swaps, (gains) losses on foreign currency swaps, impairment of available-for-sale securities, interest income, other (income) expense, (benefit) provision for income taxes, cumulative effect of a change in accounting principle, (income) loss from discontinued operations and stock-based compensation expense. The reconciliation of Adjusted EBITDA to our net income (loss) is set forth below and excludes items in our Adjusted EBITDA definition which are not applicable to the periods shown.

	Year Ended December 31,
(dollars in millions)	2018				2017				2016
Net income (loss)	$	671			$	445			$	357
Adjustments to increase (decrease) net income (loss):
Asset write-down charges	26				17				34
Acquisition and integration costs	27				61				17
Depreciation, amortization and accretion	1,528				1,242				1,109
Amortization of prepaid lease purchase price adjustments	20				20				22
Interest expense and amortization of deferred financing costs	642				591				515
(Gains) losses on retirement of long-term obligations	106				4				52
Interest income	(5		)		(19		)		(1		)
Other (income) expense	(1		)		(1		)		9
(Benefit) provision for income taxes	19				26				17
Stock-based compensation expense	108				96				97
Adjusted EBITDA(a)	$	3,141			$	2,482			$	2,228

(a)	The above reconciliation excludes the items included in our Adjusted EBITDA definition which are not applicable to the periods shown.

We believe Adjusted EBITDA is useful to investors or other interested parties in evaluating our financial performance because:

•	it is the primary measure used by our management to evaluate (1) the economic productivity of our operations and (2) for purposes of making decisions about allocating resources to, and assessing the performance of, our operations;

•	although specific definitions may vary, it is widely used by investors or other interested parties in evaluation of the communications infrastructure sector and other REITs to measure financial performance without regard to items such as depreciation, amortization and accretion which can vary depending upon accounting methods and the book value of assets;

•	we believe it helps investors and other interested parties meaningfully evaluate and compare the results of our operations (1) from period to period and (2) to our competitors by removing the impact of our capital structure (primarily interest charges from our outstanding debt) and asset base (primarily depreciation, amortization and accretion) from our financial results; and

•	it is similar to the measure of current financial performance generally used in our debt covenant calculations.

Our management uses Adjusted EBITDA:

•	as a performance goal in employee annual incentive compensation;

•	as a measurement of financial performance because it assists us in comparing our financial performance on a consistent basis as it removes the impact of our capital structure (primarily interest charges from our outstanding debt) and asset base (primarily depreciation, amortization, and accretion) from our operating results;

•	in presentations to our board of directors to enable it to have the same measurement of financial performance used by management;

•	for planning purposes, including preparation of our annual operating budget;

•	as a valuation measure in strategic analyses in connection with the purchase and sale of assets;

•	in determining self-imposed limits on our debt levels, including the evaluation of our leverage ratio and interest coverage ratio; and

•	with respect to compliance with our debt covenants, which require us to maintain certain financial ratios that incorporate concepts such as, or similar to, Adjusted EBITDA.