Cover and table of contents

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

			☑			ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2023

OR

			☐			TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)

OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission file number 001-16189

NiSource Inc.

(Exact name of registrant as specified in its charter)

DE									35-2108964
(State or other jurisdiction of incorporation or organization)									(I.R.S. Employer Identification No.)
801 East 86th Avenue
Merrillville,			IN						46410
(Address of principal executive offices)									(Zip Code)

(877) 647-5990

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class			Trading Symbol(s)			Name of Each Exchange on Which Registered
Common Stock, par value $0.01 per share			NI			NYSE
Depositary Shares, each representing a 1/1,000th ownership interest in a share of 6.50% Series B Fixed-Rate Reset Cumulative Redeemable Perpetual Preferred Stock, par value $0.01 per share, liquidation preference $25,000 per share and a 1/1,000th ownership interest in a share of Series B-1 Preferred Stock, par value $0.01 per share, liquidation preference $0.01 per share			NI PR B			NYSE

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes þ No ¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Act. Yes ¨ No þ

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.

Yes þ No ¨

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).

Yes þ No ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definition of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and "emerging growth company" in Rule 12-b-2 of the Exchange Act.

Large accelerated filer þ Accelerated Filer ¨ Emerging Growth Company ☐ Non-accelerated Filer ¨ Smaller Reporting Company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☑

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrants included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant's executive officers during the relevant recovery period pursuant to §240. 10D-1(b).☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ☐ No þ

The aggregate market value of the registrant's common stock, par value $0.01 per share (the "Common Stock") held by non-affiliates was approximately $11,285,281,624 based upon the June 30, 2023, closing price of $27.35 on the New York Stock Exchange.

There were 447,524,529 shares of Common Stock outstanding as of February 14, 2024.

Documents Incorporated by Reference

Part III of this report incorporates by reference specific portions of the Registrant’s Notice of Annual Meeting and Proxy Statement relating to the Annual Meeting of Stockholders to be held on May 13, 2024.

CONTENTS

						Page No.
Defined Terms						3
Part I
Item 1.			Business			7
Item 1A.			Risk Factors			18
Item 1B.			Unresolved Staff Comments			32
Item 1C.			Cybersecurity			32
Item 2.			Properties			32
Item 3.			Legal Proceedings			33
Item 4			Mine Safety Disclosures			33
Part II
Item 5.			Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities			34
Item 6.			Reserved			35
Item 7.			Management’s Discussion and Analysis of Financial Condition and Results of Operations			36
Item 7A.			Quantitative and Qualitative Disclosures About Market Risk			55
Item 8.			Financial Statements and Supplementary Data			56
Item 9.			Changes in and Disagreements With Accountants on Accounting and Financial Disclosure			120
Item 9A.			Controls and Procedures			120
Item 9B.			Other Information			122
Item 9C.			Disclosure Regarding Foreign Jurisdictions that Prevent Inspections			122
Part III
Item 10.			Directors, Executive Officers and Corporate Governance			123
Item 11.			Executive Compensation			123
Item 12.			Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters			123
Item 13.			Certain Relationships and Related Transactions, and Director Independence			123
Item 14.			Principal Accounting Fees and Services			123
Part IV
Item 15.			Exhibits, Financial Statement Schedules			124
Item 16.			Form 10-K Summary			130
Signatures						131

DEFINED TERMS
The following is a list of frequently used abbreviations or acronyms that are found in this report:
NiSource Subsidiaries and Affiliates (not exhaustive)
Columbia of Kentucky						Columbia Gas of Kentucky, Inc.
Columbia of Maryland						Columbia Gas of Maryland, Inc.
Columbia of Massachusetts						Bay State Gas Company
Columbia of Ohio						Columbia Gas of Ohio, Inc.
Columbia of Pennsylvania						Columbia Gas of Pennsylvania, Inc.
Columbia of Virginia						Columbia Gas of Virginia, Inc.
NIPSCO						Northern Indiana Public Service Company LLC
NIPSCO Holdings I						NIPSCO Holdings I LLC
NIPSCO Holdings II						NIPSCO Holdings II LLC
NiSource ("we," "us" or "our")						NiSource Inc.
Rosewater						Rosewater Wind Generation LLC and its wholly owned subsidiary, Rosewater Wind Farm LLC
Indiana Crossroads Solar						Indiana Crossroads Solar Generation LLC and its wholly owned subsidiary, Meadow Lake Solar Park LLC
Indiana Crossroads Wind						Indiana Crossroads Wind Generation LLC and its wholly owned subsidiary, Indiana Crossroads Wind Farm LLC
Dunns Bridge I						Dunns Bridge I Solar Generation LLC and its wholly owned subsidiary, Dunns Bridge Solar Center LLC
Dunns Bridge II						Dunns Bridge II Solar Generation LLC
Fairbanks						Fairbanks Solar Generation LLC
Cavalry						Cavalry Solar Generation LLC
Abbreviations and Other
AFUDC						Allowance for funds used during construction
AOCI						Accumulated Other Comprehensive Income (Loss)
ASC						Accounting Standards Codification
ASU						Accounting Standards Update
ATM						At-the-market
BIP						BIP Blue Buyer L.L.C
Blackstone						Blackstone Infrastructure Partners L.P.
BTA						Build-transfer agreement
CCGT						Combined Cycle Gas Turbine
CCRs						Coal Combustion Residuals
CEP						Capital Expenditure Program
CERCLA						Comprehensive Environmental Response Compensation and Liability Act (also known as Superfund)
CISA						Certified Information Systems Auditor
CISO						Chief Information Security Officer
CISSP						Certified Information Systems Security Professional
Corporate Units						Series A Corporate Units
COVID-19 ("the COVID-19 pandemic" or "the pandemic")						Novel Coronavirus 2019 and its variants, including the Delta and Omicron variants, and any other variant that may emerge
CRISC						Certified in Risk and Information Systems Control
DE&I						Diversity Equity and Inclusion
DPU						Department of Public Utilities
DSM						Demand Side Management

DEFINED TERMS
EPA						United States Environmental Protection Agency
EPS						Earnings per share
Equity Units						Series A Equity Units
FAC						Fuel adjustment clause
FASB						Financial Accounting Standards Board
FERC						Federal Energy Regulatory Commission
FMCA						Federally Mandated Cost Adjustment
GAAP						Generally Accepted Accounting Principles
GCA						Gas cost adjustment
GHG						Greenhouse gases
HLBV						Hypothetical Liquidation at Book Value
IIJA						Infrastructure Investment and Jobs Act
IRA						Inflation Reduction Act
IRP						Infrastructure Replacement Program
IRS						Internal Revenue Service
IURC						Indiana Utility Regulatory Commission
JV						Joint Venture
LDCs						Local distribution companies
LIFO						Last-in, first-out
LIHEAP						Low Income Heating Energy Assistance Programs
Massachusetts Business						All of the assets sold to, and liabilities assumed by, Eversource pursuant to the Asset Purchase Agreement
MGP						Manufactured Gas Plant
MISO						Midcontinent Independent System Operator
MMDth						Million dekatherms
MW						Megawatts
MWh						Megawatt hours
NERC CIP						North American Electric Reliability Corporation Critical Infrastructure Protection
NIPSCO Minority Interest Transaction						A transaction between NiSource, NIPSCO Holdings II (sole owner of NIPSCO) and an affiliate of Blackstone pursuant to a purchase and sale agreement entered into on June 17, 2023, that offered equity interests in NIPSCO Holdings II in exchange for capital contributions by the parties.
NOL						Net Operating Loss
NTSB						National Transportation Safety Board
NYMEX						The New York Mercantile Exchange
OPEB						Other Postretirement and Postemployment Benefits
OT						Operational Technology
PCB						Polychlorinated biphenyls
PHMSA						Pipeline and Hazardous Materials Safety Administration
PPA						Power Purchase Agreement
PSC						Public Service Commission
PUCO						Public Utilities Commission of Ohio
ROE						Return on Equity
RNG						Renewable Natural Gas
ROU						Right of Use
SAVE						Steps to Advance Virginia's Energy Plan

DEFINED TERMS
Scope 1 GHG Emissions						Direct emissions from sources owned or controlled by us (e.g., emissions from our combustion of fuel, vehicles, and process emissions and fugitive emissions)
Scope 2 GHG Emissions						Indirect emissions from sources owned or controlled by us
SEC						Securities and Exchange Commission
Section 201 Tariffs						Tariffs imposed by Executive Order from the President of the U.S. on certain imported solar cells and modules at a rate of 15%, which were recently extended to 2026
SMRP						Safety Modification and Replacement Program
SMS						Safety Management System
SOFR						Secured Overnight Financing Rate
STRIDE						Strategic Infrastructure Development and Enhancement
TCJA						An Act to provide for reconciliation pursuant to titles II and V of the concurrent resolution on the budget for fiscal year 2018 (commonly known as the Tax Cuts and Jobs Act of 2017)
TDSIC						Transmission, Distribution and Storage System Improvement Charge
TSA						Transportation Security Administration
U.S. Attorney's Office						U.S. Attorney's Office for the District of Massachusetts
VIE						Variable Interest Entity

Note regarding forward-looking statements

This Annual Report on Form 10-K contains "forward-looking statements," within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act"), and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"). Investors and prospective investors should understand that many factors govern whether any forward-looking statement contained herein will be or can be realized. Any one of those factors could cause actual results to differ materially from those projected. These forward-looking statements include, but are not limited to, statements concerning our plans, strategies, objectives, expected performance, expenditures, recovery of expenditures through rates, stated on either a consolidated or segment basis, and any and all underlying assumptions and other statements that are other than statements of historical fact. Expressions of future goals and expectations and similar expressions, including "may," "will," "should," "could," "would," "aims," "seeks," "expects," "plans," "anticipates," "intends," "believes," "estimates," "predicts," "potential," "targets," "forecast," and "continue," reflecting something other than historical fact are intended to identify forward-looking statements. All forward-looking statements are based on assumptions that management believes to be reasonable; however, there can be no assurance that actual results will not differ materially.

Factors that could cause actual results to differ materially from the projections, forecasts, estimates and expectations discussed in this Annual Report on Form 10-K include, among other things:

• our ability to execute our business plan or growth strategy, including utility infrastructure investments;

• potential incidents and other operating risks associated with our business;

• our ability to work successfully with our third-party investors;

• our ability to adapt to, and manage costs related to, advances in technology, including alternative energy sources and changes in laws and regulations;

• our increased dependency on technology;

• impacts related to our aging infrastructure;

• our ability to obtain sufficient insurance coverage and whether such coverage will protect us against significant losses;

• the success of our electric generation strategy;

• construction risks and supply risks;

• fluctuations in demand from residential and commercial customers;

• fluctuations in the price of energy commodities and related transportation costs or an inability to obtain an adequate, reliable and cost-effective fuel supply to meet customer demand;

• our ability to attract, retain or re-skill a qualified, diverse workforce and maintain good labor relations;

• our ability to manage new initiatives and organizational changes;

• the actions of activist stockholders;

• the performance and quality of third-party suppliers and service providers;

• potential cybersecurity attacks or security breaches;

• increased requirements and costs related to cybersecurity;

• any damage to our reputation;

• the impacts of natural disasters, potential terrorist attacks or other catastrophic events;

• the physical impacts of climate change and the transition to a lower carbon future;

• our ability to manage the financial and operational risks related to achieving our carbon emission reduction goals, including our Net Zero Goal (as defined below);

• our debt obligations;

• any changes to our credit rating or the credit rating of certain of our subsidiaries;

• adverse economic and capital market conditions, including increases in inflation or interest rates, recession, or changes in investor sentiment;

• economic regulation and the impact of regulatory rate reviews;

• our ability to obtain expected financial or regulatory outcomes;

• economic conditions in certain industries;

• the reliability of customers and suppliers to fulfill their payment and contractual obligations;

• the ability of our subsidiaries to generate cash;

• pension funding obligations;

• potential impairments of goodwill;

• the outcome of legal and regulatory proceedings, investigations, incidents, claims and litigation;

• compliance with changes in, or new interpretations of applicable laws, regulations and tariffs;

• the cost of compliance with environmental laws and regulations and the costs of associated liabilities;

• changes in tax laws or the interpretation thereof;

• and other matters set forth in Item 1, "Business," Item 1A, "Risk Factors" and Part II, Item 7, "Management’s Discussion and Analysis of Financial Condition and Results of Operations," of this report, some of which risks are beyond our control.

In addition, the relative contributions to profitability by each business segment, and the assumptions underlying the forward-looking statements relating thereto, may change over time.

All forward-looking statements are expressly qualified in their entirety by the foregoing cautionary statements. We undertake no obligation to, and expressly disclaim any such obligation to, update or revise any forward-looking statements to reflect changed assumptions, the occurrence of anticipated or unanticipated events or changes to the future results over time or otherwise, except as required by law.

PART I

ITEM 1. BUSINESS

NIS****OURCE INC.

NiSource Inc. is an energy holding company under the Public Utility Holding Company Act of 2005 whose primary subsidiaries are fully regulated natural gas and electric utility companies, serving approximately 3.8 million customers in six states. NiSource is the successor to an Indiana corporation organized in 1987 under the name of NIPSCO Industries, Inc., which changed its name to NiSource Inc. on April 14, 1999.

On November 7, 2022, we announced our intention to seek a minority interest investor in NIPSCO. We entered into an agreement with Blackstone on June 17, 2023, in furtherance of this goal. On December 31, 2023, the NIPSCO Minority Interest Transaction closed. At closing, NIPSCO Holdings I contributed all its membership interests in NIPSCO in exchange for an 80.1% controlling membership interest and Blackstone contributed $2.16 billion in cash in exchange for a 19.9% membership interest in NIPSCO Holdings II, respectively. NIPSCO Holdings II owns all the membership interests in NIPSCO.

NiSource’s principal subsidiaries include NiSource Gas Distribution Group, Inc. (a holding company that owns Columbia of Kentucky, Columbia of Maryland, Columbia of Ohio, Columbia of Pennsylvania, and Columbia of Virginia), and a controlling interest in NIPSCO (a gas and electric company). NiSource derives substantially all of its revenues and earnings from the operating results of these rate-regulated businesses.

Business Strategy

Our business strategy focuses on providing safe and reliable service through our core, rate-regulated, asset-based utilities, with the goal of adding value to all of our stakeholders. Our utilities continue to advance our core safety, infrastructure and environmental investment programs supported by complementary regulatory and customer initiatives across the six states in which we operate. Our goal is to develop strategies that (i) support long-term infrastructure investment and safety programs to better serve our customers, (ii) align our tariff structures with our cost structure, and (iii) drive value and enable growth in an evolving energy ecosystem. These strategies focus on improving safety and reliability, enhancing customer experience, pursuing regulatory and legislative initiatives to increase accessibility for customers currently not on our gas and electric service, ensuring customer affordability and reducing emissions while generating sustainable returns.

We remain committed to the advancement of our SMS for the safety of our customers, communities and employees. Our SMS is the established operating model within NiSource. In 2022, we achieved conformance certification to the American Petroleum Institute Recommended Practice 1173, which serves as the guiding practice for our SMS. This certification, which requires ongoing annual review, marked an important milestone for our SMS and NiSource’s journey towards operational excellence. Our focus is maintaining, sustaining and continuously improving processes, procedures, capabilities and talent to enhance safety and reduce operational risk.

NiSource has two reportable segments: Gas Distribution Operations and Electric Operations. The remainder of our operations, which are not significant enough on a stand-alone basis to warrant treatment as an operating segment, are included as Corporate and Other. The activities occurring within this non-segment consist of our centralized corporate activities and are primarily comprised of interest expense on holding company debt and unallocated corporate costs and activities. The following is a summary of the business for each reporting segment. Refer to Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and Note 21, "Business Segment Information," in the Notes to Consolidated Financial Statements for additional information related to each segment.

Gas Distribution Operations

Our natural gas distribution operations serve approximately 3.3 million customers in six states. Through our wholly-owned subsidiary NiSource Gas Distribution Group, Inc., we provide natural gas to approximately 2.4 million residential, commercial and industrial customers in Ohio, Pennsylvania, Virginia, Kentucky, and Maryland. Additionally, we distribute natural gas to approximately 0.9 million customers in northern Indiana through our subsidiary NIPSCO. We operate approximately 55,000 miles of distribution main pipeline plus the associated individual customer service lines and 1,000 miles of transmission main pipeline located in our service areas described below. Throughout our service areas we also have gate stations and other operations support facilities. See below for information on our owned operating facilities. There were no significant disruptions to our system or facilities during 2023.

ITEM 1. BUSINESS

NIS****OURCE INC.

Facility Name						Location			Type			Storage Capacity (MCF)
Royal Center Underground Storage						Royal Center, IN			Natural Gas			7,240,000
Rolling Prairie LNG						Rolling Prairie, IN			Liquified Natural Gas			4,000,000
Blackhawk Underground Storage						Beaver Falls, PA			Natural Gas			1,700,000
Eagle Cove Propane						Petersburgh, VA			Propane Gas			863
South Wales Propane						Jeffersonton, VA			Propane Gas			863
Portsmouth Propane-Air						Portsmouth, VA			Propane-Air Gas			17,300
Total Capacities												12,959,026

Competition. Open access to natural gas supplies over interstate pipelines and the deregulation of the natural gas supply has led to tremendous change in the energy markets and natural gas competition. Due to open access to natural gas supplies, our LDC customers can purchase gas directly from producers and marketers in an open, competitive market. Certain of our Gas Distribution Operations’ subsidiaries are involved in programs that provide our residential and commercial customers the opportunity to purchase their natural gas requirements from third parties and use our Gas Distribution Operations’ subsidiaries for transportation services. As of December 31, 2023, 25.9% of our residential customers and 34.7% of our commercial customers participated in such programs.

Gas Distribution Operations competes with (i) investor-owned, municipal, and cooperative electric utilities throughout its service areas, (ii) other regulated and unregulated natural gas intra and interstate pipelines and (iii) other alternate fuels, such as propane and fuel oil. Gas Distribution Operations continues to be a strong competitor in the energy markets in which it operates as a result of strong customer preference for natural gas. Competition with providers of electricity has traditionally been the strongest in the residential and commercial markets of Kentucky, southern Ohio, central Pennsylvania and western Virginia due to comparatively low electric rates.

Additionally, our gas distribution operations are subject to seasonal fluctuations in sales. Revenues from gas distribution operations are more significant during the heating season, which is primarily from November through March. Please refer to Part II, Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations - Results and Discussion of Operations - Gas Distribution Operations," for additional information.

Electric Operations

We generate, transmit and distribute electricity through our subsidiary NIPSCO to approximately 0.5 million customers in 20 counties in the northern part of Indiana and also engage in wholesale electric and transmission transactions. We own and operate sources of generation as well as source power through PPAs. We continue to transition our generation portfolio to primarily renewable sources. We currently have four owned projects in service: Rosewater, Indiana Crossroads Wind, Indiana Crossroads Solar, and Dunns Bridge I. Rosewater went into service in December 2020 and Indiana Crossroads Wind went into service in December 2021. The Indiana Crossroads Solar and Dunns Bridge I Solar projects went into service in June 2023. In October 2021, NIPSCO completed the retirement of two coal-burning units with installed capacity of approximately 903 MW at Schahfer Generating Station, located in Wheatfield, IN. As of December 31, 2023, we have multiple PPAs that provide 700 MW of capacity, with contracts expiring between 2024 and 2040.

NIPSCO’s transmission system, with voltages from 69,000 to 765,000 volts, consists of approximately 2,920 circuit miles. NIPSCO is interconnected with eight neighboring electric utilities.We operate 66 transmission and 250 distribution substations, and own approximately 311,000 poles. Additionally, we own and operate reactive resources to supplement generation when necessary. Our facilities had no material unplanned interruptions during 2023. See below for information on our owned operating facilities:

ITEM 1. BUSINESS

NIS****OURCE INC.

Facility Name						Location			Fuel Type			Generating Capacity (MW)****(1)
R.M. Schahfer						Wheatfield, IN			Steam - Coal			722
Michigan City						Michigan City, IN			Steam - Coal			455
Sugar Creek(2)						West Terre Haute, IN			CCGT			563
R.M. Schahfer						Wheatfield, IN			Natural Gas			155
Oakdale						Carroll County, IN			Hydro			9
Norway						White County, IN			Hydro			7
Rosewater(3)						White County, IN			Wind			102
Indiana Crossroads Wind(3)						White County, IN			Wind			302
Dunns Bridge I(3)						Jasper County, IN			Solar			265
Indiana Crossroads Solar(3)						White County, IN			Solar			200
Total MW Capacity												2,780

(1)Represents current net generating capability of each fossil fuel and hydro generating facility. Nameplate capacity is listed for wind and solar generating facilities.

(2)Sugar Creek added additional generating capacity in January 2024.

(3)NIPSCO is the managing partner of these JVs. Refer to Note 4, "Noncontrolling Interest," in the Notes to Consolidated Financial Statements for more information.

In November 2021, NIPSCO submitted its 2021 Integrated Resource Plan ("2021 Plan") with the IURC. The 2021 Plan builds upon the 2018 Integrated Resource Plan which outlined NIPSCO’s plan to retire its coal generating assets by 2028. The 2021 Plan affirmed the 2018 retirement decisions and calls for the replacement of the retiring coal generating assets with a diverse portfolio of resources, including demand side management resources, incremental solar, stand-alone energy storage, new gas peaking resources and upgrades to existing facilities at the Sugar Creek Generating Station, among other steps. Refer to Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations” for further discussion of these plans.

NIPSCO participates in the MISO transmission service and wholesale energy market. MISO is a nonprofit organization created in compliance with FERC regulations to improve the flow of electricity in the regional marketplace and to enhance electric reliability. Additionally, MISO is responsible for managing energy markets, transmission constraints and the day-ahead, real-time, Financial Transmission Rights and ancillary markets. NIPSCO has transferred functional control of its electric transmission assets to MISO, and transmission service for NIPSCO occurs under the MISO Open Access Transmission Tariff. NIPSCO generating units are dispatched by MISO which takes into account economics, reliability of the MISO system and unit availability. During the year ended December 31, 2023, NIPSCO generating units, inclusive of its BTA projects, were dispatched to meet 49.5% of its overall system load, and the remainder of the overall system load was procured through PPAs and the MISO market.

Competition. Our electric utility generally has exclusive service areas under Indiana regulations, and retail electric customers in Indiana do not have the ability to choose their electric supplier. NIPSCO faces non-utility competition from other energy sources, such as self-generation by large industrial customers and other distributed energy sources.

Our electric operations are subject to seasonal fluctuations in sales. Revenues from electric operations are more significant during the cooling season, which is primarily from June through September. Please refer to Part II, Item 7, "Management's Discussion and Analysis of Financial Condition and Results of Operations - Results and Discussion of Operations - Electric Operations," for additional information.

Political Action

The NiSource Political Action Committee ("NiPAC") provides our employees a voice in the political process. NiPAC is a voluntary, employee and director driven and funded political action committee, and NiPAC makes bipartisan political contributions to local, state and federal candidates where permitted and in accordance with established guidelines. Consistent with our commitments and our approach to engagement, the NiPAC leadership committee members evaluate candidates for support on issues important to our business.

ITEM 1. BUSINESS

NIS****OURCE INC.

Regulatory

The applicable regulatory landscape at both the state and federal levels continue to evolve, including environmental. These changes have had and will continue to have an impact on our operations, structure and profitability. Management continually seeks new ways to be more competitive and profitable in this environment, while keeping service and affordability for customers at the forefront. We believe we are, in all material respects, in compliance with such laws and regulations and do not expect future compliance changes to have a material impact on our capital expenditures, earnings, or competitive position. We continue to monitor existing and pending laws and regulations, and the impact of regulatory changes cannot be predicted with certainty.

Rate Case Actions. The following table describes current rate case actions as applicable in each of our jurisdictions net of tracker impacts. See "Cost Recovery and Trackers" below for further detail on trackers.

(in millions)
Company			Approved ROE			Requested Incremental Revenue			Approved Incremental Revenue			Filing Date			Rates Effective
Approved Rates Cases
Columbia of Pennsylvania(1)			None specified			$	82.2		$	44.5		March 18, 2022			December 2022
Columbia of Maryland(1)			None specified			$	6.5		$	3.9		May 12, 2023			December 2023
Columbia of Kentucky(2)			9.35		%	$	26.7		$	18.3		May 28, 2021			January 2022
Columbia of Virginia(3)			None specified			$	40.5		$	25.8		April 29, 2022			October 2022
Columbia of Ohio			9.60		%	$	221.4		$	68.3		June 30, 2021			March 2023
NIPSCO - Gas(4)			9.85		%	$	109.7		$	71.8		September 29, 2021			September 2022
NIPSCO - Electric(5)			9.80		%	$	291.8		$	261.9		September 19, 2022			August 2023
Pending Rate Cases
NIPSCO - Gas(6)			In process			$	161.9		In process			October 25, 2023			September 2024

(1) No approved ROE is identified for this matter since the approved revenue increase is the result of a black box settlement under which parties agree upon the amount of increase.

(2)The approved ROE for natural gas capital riders (e.g.,SMRP) is 9.275%.

(3)Columbia of Virginia's rate case resulted in a black box settlement, representing a settlement to a specific revenue increase but not a specified ROE. The settlement provides use of a 9.70% ROE for future SAVE filings.

(4)New rates were implemented in 2 steps, with implementation of Step 1 rates in September 2022. The Step 2 rates were filed on February 21, 2023, with rates effective March 2023.

(5)New rates will be implemented in 2 steps, with implementation of Step 1 rates in August 2023 and Step 2 Rates to be effective in March 2024, with service provided in February 2024.

(6)Pending the outcome of the current case, new rates are expected to be implemented in 2 steps, with implementation of Step 1 rates to be effective in September 2024 and Step 2 Rates in March 2025.

ITEM 1. BUSINESS

NIS****OURCE INC.

FERC. NiSource’s service company and operating companies are subject to varying degrees of regulation by the FERC. NiSource Corporate Services files a FERC Form 60 annual report with its financial information as a FERC jurisdictional centralized service company. NiSource also files an annual FERC Form 61 which contains a narrative description of the service company's functions during the prior calendar year.

As natural gas LDCs, Columbia of Maryland, Columbia of Ohio, Columbia of Pennsylvania, Columbia of Virginia, and NIPSCO have limited jurisdictional certificates to transport gas in the respective service territories into interstate commerce.

As an electric company, NIPSCO has Market Based Rate authority and is a Transmission Owner subject to FERC jurisdiction. NIPSCO files the following reports annually:

• FERC Form 1, which is a comprehensive financial and operating report,

• FERC Form 566, which is a list of its 20 largest purchases of electricity over the past three years,

• FERC Form 715, which is its Annual Transmission Planning and Evaluation Report and the base case power flow data from the Eastern Interconnection Reliability Assessment Group Multiregional Modeling Working Group, which was used by NIPSCO for transmission planning and,

• FERC Form 730, which is NIPSCO’s Report of Transmission Investment Activity.

As a Transmission Owner subject to the MISO Transmission Owners Agreement and Tariff, NIPSCO has various FERC jurisdictional obligations such as maintaining its Attachment O formula rates and corresponding protocols. NIPSCO also has FERC approvals to make affiliate transactions between itself and various JVs. NIPSCO’s officers, on the electric side, are also subject to FERC’s interlocking directorate rules and reporting requirements.

Regulatory Framework. The Gas Distribution Operations utilities have pursued non-traditional revenue sources within the evolving natural gas marketplace. These efforts include (i) the sale of products and services in the companies’ service territories, and (ii) gas supply cost incentive mechanisms for service to their core markets. The on-system services are offered by us to customers and include products such as the transportation and balancing of gas on the Gas Distribution Operations utility's system. The incentive mechanisms give the Gas Distribution Operations utilities an opportunity to share in the savings created from such situations as gas purchases made below an agreed upon benchmark price and the remarketing of unused pipeline capacity to reduce overall pipeline costs.

We recognize that energy efficiency reduces emissions, conserves natural resources and saves our customers money. Our gas distribution companies offer programs such as energy efficiency upgrades, home checkups and weatherization services. The increased efficiency of natural gas appliances and improvements in home building codes and standards contribute to a long-term trend of declining average use per customer. While we are looking to expand offerings so the energy efficiency programs can benefit as many customers as possible, our Gas Distribution Operations have pursued changes in rate design to more effectively match recoveries with costs incurred. Columbia of Ohio has adopted a straight fixed variable rate design that closely links the recovery of fixed costs with fixed charges. Columbia of Maryland and Columbia of Virginia have regulatory approval for weather and revenue normalization adjustments for certain customer classes, which adjust monthly revenues that exceed or fall short of approved levels. Columbia of Pennsylvania continues to operate its pilot residential weather normalization adjustment and also has a fixed customer charge. This weather normalization adjustment only adjusts revenues when actual weather compared to normal varies by more than 3%. Columbia of Kentucky incorporates a weather normalization adjustment for certain customer classes and also has a fixed customer charge. NIPSCO Gas and Electric include a fixed customer charge for residential and small commercial and industrial customer classes, but has no weather or usage protection mechanism. In its pending gas rate case, NIPSCO has requested approval of a revenue decoupling mechanism.

While increased efficiency of electric appliances and improvements in home building codes and standards have similarly impacted the average use per electric customer in recent years, NIPSCO expects future growth in per customer usage as a result of increasing electric applications. Further growth is anticipated as electric vehicles become more prevalent. These ongoing changes in use of electricity will likely lead to development of innovative rate designs, and NIPSCO will continue efforts to design rates that increase the certainty of recovery of fixed costs.

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Cost Recovery and Trackers. Comparability of our line item operating results is impacted by regulatory trackers that allow for the recovery in rates of certain costs such as those described below. Increases in the expenses that are subject to approved regulatory tracker mechanisms generally lead to increased regulatory assets, which ultimately result in a corresponding increase in operating revenues and, therefore, have essentially no impact on total operating income results. Certain approved regulatory tracker mechanisms allow for abbreviated regulatory proceedings in order for the operating companies to quickly implement revised rates and recover associated costs.

A portion of the Gas Distribution Operations revenue is related to the recovery of gas costs, the review and recovery of which occurs through standard regulatory proceedings. All states in our operating area require periodic review of actual gas procurement activity to determine prudence and confirm the recovery of prudently incurred energy commodity costs supplied to customers.

A portion of the Electric Operations revenue is related to the recovery of fuel costs to generate power and the fuel costs related to purchased power. These costs are recovered through a FAC, which is updated quarterly to reflect actual costs incurred to supply electricity to customers.

Environmental and Safety Matters

We are committed to reducing the environmental impact of our business and promoting sustained environmental stewardship. We seek proactive opportunities for improved environmental performance and are committed to complying with environmental laws and regulations. To fulfill our vision of being a trusted energy provider, we follow safety practices recommended by leading industry organizations. These practices help us identify and address potential risks, resulting in improvements to our operational and environmental safety.

PHMSA Legislation and Regulations

Under the Protecting Our Infrastructure of Pipelines and Enhancing Safety (PIPES) Act of 2020, PHMSA has revised, and continues to revise, the pipeline safety regulations to require operators to update, as needed, their existing distribution integrity management plans, emergency response plans, and operation and maintenance plans. PHMSA has also adopted new requirements for managing records and updating, as necessary, existing district regulator stations to eliminate common modes of failure that can lead to over-pressurization.

In May 2023, PHMSA proposed numerous regulatory revisions under the PIPES Act of 2020 to minimize methane emissions and improve public safety. Under these proposed revisions, our subsidiaries would be required to detect and repair an increased number of gas leaks, reduce the time to repair leaks, increase leak survey frequency, and expand our existing advanced leak detection program. We continue to evaluate the proposed rule for additional impacts on our business.

In September 2023, PHMSA proposed additional regulatory revisions under the PIPES Act of 2020 to enhance distribution system safety through equipment and procedural expectations. Operators will be required to incorporate additional protections for low pressure distribution systems that prevent over-pressurization, amend construction procedures designed to minimize the risk of incidents caused by system over-pressurization, and update distribution integrity management programs to cover and prepare for over-pressurization incidents.

On November 30, 2023, the House Transportation & Infrastructure Committee introduced new pipeline safety reauthorization legislation known as the PIPES Act of 2023 to reauthorize PHMSA’s safety programs for the next four years. The proposed legislation includes several priorities for our company, including excavation damage prevention grants to improve states’ damage prevention programs, a PHMSA study on blending hydrogen in distribution pipelines, new criminal penalties for intentionally damaging pipeline facilities, and creation of a Voluntary Information Sharing System to allow for industry participants to share learnings and best practices in a protected manner across the pipeline industry.

CCR Regulation

In May 2023, the EPA proposed changes to the CCR regulations for inactive surface impoundments at inactive facilities, referred to as legacy CCR surface impoundments. The EPA is also proposing to extend a subset of requirements in the CCR regulations to areas not previously subject to the CCR regulations, referred to as CCR management units ("CCRMUs"). In November 2023, the EPA issued a Notice of Data Availability seeking comment on updated lists of legacy impoundments and CCRMUs, as well as a risk assessment for legacy impoundments and CCRMUs. We continue to evaluate the proposed rule for impacts on our business.

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Climate Change Issues

Physical Climate Risks. Increased frequency of severe and extreme weather events associated with climate change could materially impact our facilities, energy sales, and results of operations. We are unable to predict these events. However, we perform ongoing assessments of physical risk, including physical climate risk, to our business. More extreme and volatile temperatures, increased storm intensity and flooding, and more volatile precipitation leading to changes in lake and river levels are among the weather events that are most likely to impact our business. Efforts to mitigate these physical risks continue to be implemented on an ongoing basis.

Transition Climate Risks**.** We actively engage with and monitor the impact that proposed legislative and regulatory programs related to GHG emissions, at both the federal and state levels, would have on our business. Refer to Item 1A. Risk Factors, "Operational Risks," of this Annual Report on Form 10-K for further detail.

Regarding federal policies, we continue to monitor the implementation of any final and proposed climate change-related legislation and regulation, including the IIJA, IRA, EPA's final methane regulations for the oil and natural gas industry, and EPA's proposed Waste Emissions Charge for Petroleum and Natural Gas systems. We have identified potential opportunities associated with the IIJA and the IRA and are evaluating how they may align with our strategy going forward. The energy-related provisions of the IIJA include new federal funding for power grid infrastructure and resiliency investments, new and existing energy efficiency and weatherization programs, electric vehicle infrastructure for public chargers and additional LIHEAP funding. The IRA contains climate and energy provisions, including funding to decarbonize the electric sector.

The United States is a party to the Paris Agreement, an international treaty through which parties set nationally determined contributions to reduce GHG emissions, build resilience, and adapt to the impacts of climate change. The Biden Administration has set a target for the United States to achieve a 50%-52% GHG reduction from 2005 levels by 2030, which supports the President's goals to create a carbon-free power sector by 2035 and net zero emissions economy no later than 2050. There are many potential pathways to reach these goals.

In December 2023, the U.S. Department of Energy ("DOE") amended the congressionally-mandated efficiency standards for residential home furnaces manufactured after December 2028. We are assessing the potential impacts associated with these new standards.

The DOE has selected two hydrogen hubs in our territories as recipients of funding designated in the IIJA to support the development of regional clean hydrogen hubs. The two hubs are the Midwest Alliance for Clean Hydrogen Hub (MachH2), with potential projects across Illinois, Indiana, Kentucky, Michigan, Missouri, and Wisconsin; and the Appalachian Regional Clean Hydrogen Hub (ARCH2), with potential investments across West Virginia, Ohio, Kentucky, and Pennsylvania. Work is underway to determine what roles our companies may have with these hydrogen hubs.

In May 2023, the EPA released a package of proposed regulatory actions to reduce carbon dioxide emissions from new natural gas-fired electric generating units ("EGUs"), existing natural gas-fired EGUs, and existing coal-fired EGUs. We are reviewing the potential impacts of the proposed rules.

We also continue to monitor the implementation of any final and proposed state policy. The Virginia Energy Innovation Act, enacted into law in April 2022, and effective July 1, 2022, allows natural gas utilities to supply alternative forms of gas that meet certain standards and reduce emissions intensity. The Act also provides that the costs of enhanced leak detection and repair may be added to a utility’s plan to identify proposed eligible infrastructure replacement projects and related cost recovery mechanisms, known as the SAVE Plan. Furthermore, under the Act, utilities can recover eligible biogas supply infrastructure costs on an ongoing basis. The provisions of these laws may provide opportunities for Columbia of Virginia as it participates in the transition to a lower carbon future.

The Climate Solutions Now Act of 2022 requires Maryland to reduce GHG emissions by 60% by 2031 (from 2006 levels), and it requires the state to reach net zero emissions by 2045. The Maryland Department of the Environment adopted a plan to achieve its 2031 goal and is required to adopt a plan for their 2045 net zero goal by 2030. The Act also enacts a state policy to move to broader electrification of both existing buildings and new construction, and requires the PSC to complete a study assessing the capacity of gas and electric distribution systems to successfully serve customers under a transition to a highly electrified building sector. The PSC released their report on December 29, 2023, and concluded that high levels of electrification can be handled by Maryland's electric systems through 2031. On December 15, 2023, the Maryland Department of the Environment issued proposed Building Energy Performance Standards (BEPS), which would require net zero direct greenhouse gas emissions from large buildings by 2040 with interim targets. Comments on the proposed action were due to the agency on January 18, 2024. Columbia of Maryland is advocating for compliance pathways that use RNG, hydrogen, and emissions offsets. Separately, the PSC has also initiated a proceeding related to Near-Term, Priority Actions and

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Comprehensive, Long-Term Planning for Maryland's Gas Companies. Columbia of Maryland will continue to monitor these matters, but we cannot predict their final impact on our business at this time.

NIPSCO Gas, Columbia of Maryland, Columbia of Pennsylvania, Columbia of Virginia and Columbia of Kentucky each filed petitions to implement the Green Path Rider, which is a voluntary rider allowing customers to opt in and offset either 50% or 100% of their natural gas related emissions. To reduce the emissions, the utilities will purchase RNG attributes and carbon offsets to match the usage for customers opting into the program. The program was approved by the IURC at NIPSCO in November 2022 with a January 2023 start date. After reaching settlement with other parties in September 2022, NIPSCO agreed to add a third tier to offset 25% of customer usage. Columbia of Virginia received a final order in May 2023, approving the Green Path Rider and began enrolling customers in September 2023. The petitions filed by Columbia of Maryland, Columbia of Pennsylvania, and Columbia of Kentucky were rejected and have not been implemented as of December 31, 2023. Additionally, NIPSCO Electric has a voluntary Green Power Rider program in place that allows customers to designate a portion or all their monthly electric usage to come from power generated by renewable energy sources.

Net Zero Goal. In November 2022, we announced a goal of net zero greenhouse gas emissions by 2040 covering both Scope 1 and Scope 2 GHG emissions ("Net Zero Goal"). Our Net Zero Goal builds on greenhouse gas emission reductions achieved to-date and demonstrates that continued execution of our long-term business plan will drive further greenhouse gas emission reductions. We remain on track to achieve previously announced interim greenhouse gas emission reduction targets by reducing fugitive methane emissions from main and service lines by 50 percent from 2005 levels by 2025 and reducing Scope 1 GHG emissions from company-wide operations by 90 percent from 2005 levels by 2030. We plan to achieve our Net Zero Goal primarily through continuation and enhancement of existing programs, such as retiring and replacing coal-fired electric generation with low- or zero-emission electric generation, ongoing pipe replacement and modernization programs, and deployment of advanced leak-detection technologies. In addition, we plan to advance other low- or zero-emission energy resources and technologies, which may include hydrogen, renewable natural gas, long-duration storage, and/or deployment of carbon capture and utilization technologies, if and when these become technologically and economically feasible. Carbon offsets and renewable energy credits may also be used to support achievement of our Net Zero Goal. As of the end of 2022, we had reduced Scope 1 GHG emissions by approximately 67% from 2005 levels.

Our greenhouse gas emissions projections, including achieving a Net Zero Goal, are subject to various assumptions that involve risks and uncertainties. Achievement of our Net Zero Goal by 2040 will require supportive regulatory and legislative policies, favorable stakeholder environments and advancement of technologies that are not currently economical to deploy. Should such regulatory and legislative policies, stakeholder environments or technologies fail to materialize, our actual results or ability to achieve our Net Zero Goal, including by 2040, may differ materially.

As discussed in Management's Discussion within "Results and Discussion of Operations - Electric Operations," NIPSCO continues to execute on an electric generation transition consistent with the preferred pathways identified in its 2018 and 2021 Integrated Resource Plans. Additionally, as discussed in Management's Discussion within "Liquidity and Capital Resources - Regulatory Capital Programs," our natural gas distribution companies are lowering methane emissions by replacing aging infrastructure, which also increases safety and reliability for customers and communities.

Human Capital

Human Capital Management Governance and Organizational Practices. The Compensation and Human Capital Committee ("C&HC Committee") of our Board of Directors (the "Board") is primarily responsible for assisting the Board in overseeing our human capital management practices. The C&HC Committee reviews our human capital management function and programs. The review of related procedures, programs, policies and practices allows the committee to make recommendations to management with respect to equal employment opportunity and DE&I initiatives, employee engagement, corporate culture, and talent management.

In addition to overseeing our human capital management practices, our Board is committed to equal opportunity and valuing diversity. We have a goal that the Board is comprised of directors with diverse skills, expertise, experience, and demographics, including racial and gender diversity.

Human Capital Goals and Objectives*.* We have aligned our human capital goals to achieve overall company strategic and operational objectives by driving an enhanced talent strategy, elevating support for front-line leaders, fostering a culture of rigor and accountability, and strengthening our human resource function. We aspire to be an employer of choice in the utility industry, in part, through embedding DE&I throughout the enterprise and creating an enviable employee experience.

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Workforce Composition*.* As of December 31, 2023, we had 7,364 full-time and 47 part-time active employees (i.e., not interns, not on leave or disability). Of our total workforce, 34% were subject to collective bargaining agreements with various labor unions. These collective bargaining agreements were renegotiated in 2021 and 2023 and expire in 2026 and 2027, respectively.

Diversity, Equity and Inclusion*.* We foster an enviable work environment that embraces DE&I and where all employees are energized. In efforts to become an employer of choice, we have developed sourcing strategies to attract and retain the most qualified talent. Our executive leadership team is characterized by a diverse composition, with 75% representation from both POC and females. In additional we have made progress the last several years with growth in our overall female and POC population.

In 2023, our Diversity of Slate initiative contributed to our talent acquisition team filling 1,508 roles with 579 filled by external candidates. Our efforts in 2023 resulted in 32% of external hires being racially or ethnically diverse and 49% being female. Our sourcing efforts led our organization across all businesses to create a workforce composition that embraces all different perspectives. We believe that every move we make as a company must value and advance the interests of the individual, energize our communities, and serve as another step toward establishing a society where no one is left behind.

A company that works to become truly fair and inclusive opens the door to more voices being heard. Our employee resource groups (ERGs) serve to create a culture of inclusion through their engagement of all employees throughout the year. We continue to develop ERG leaders to equip employees with the necessary tools to further support our efforts for advancement and strengthen our inclusive workplace. A key area for us has been our implementation and development of programs to drive higher retention and engagement of our employees. Our commitment is grounded on the core belief that our purpose extends far beyond our primary role as a utility company; thus, we focused on inclusive leadership training for over 700 Directors and Managers in the organization.

We are committed to providing equal employment opportunities in each of our companies to all employees and applicants without regard to race, color, religion, national origin or ancestry, veteran status, disability, gender, age, marital status, sexual orientation, gender identity, genetic information, or any protected group status as defined by law. The input provided by our increasingly diverse workforce will continue to strengthen our corporate culture as well as drive constructive changes within our company to improve our operational strategies, enhance the quality of the services we provide, and increase revenue.

Talent Attraction. To recruit and hire individuals with a variety of skills, talents, backgrounds and experiences, we value and cultivate relationships with community and diversity outreach partners. We also target job fairs, including those focused on people of color and veteran and female candidates and partner with local colleges and universities to identify and recruit qualified applicants in the communities we serve.

Similar to other companies we focused on our future of work and creating a flexible, agile model for roles that can be performed in a more remote setting. Our hybrid model recognizes differing ways of working; onsite, hybrid and remote. Most of our workforce is onsite (56%) and our hybrid (36%) and remote (7%) roles provide different avenues of working and seeking talent across our footprint. Hybrid employees work in a NiSource facility twice a week. This in-office presence supports colleague connection, development, in-person mentoring, and broader team building.

As an investment in our talent attraction in 2023, our NiSource Candidate Relationship Management (CRM) was brought online enabling interface with potential candidates and pools of candidates through a talent network even when active recruiting may not be in progress. We are proud to be one of TIME magazine’s World’s Best Companies of 2023 and recognized to the Forbes 2023 list of Best Employers for Diversity.

Talent Development and Retention*.* We offer leadership development programs to enhance the behaviors and skills of our existing and future leaders. In 2023, we had participation from employees of all levels. We also offer extensive technical and non-technical employee development training programs.

We strive to provide promotion and advancement opportunities for employees. In 2023, for all leadership positions at the supervisor and above level posted externally, we filled 72% with internal employees. We also develop and implement targeted development action plans to increase succession candidate readiness for leadership roles. Additionally, we monitor the risk and potential impact of talent loss and take action to increase retention of top talent. Retention in 2023 was over 93%. We calculate retention as 100 minus the total number of separations divided by the average headcount for the annual period. These