NiSource NI · USD

Our reportable segments reflect the manner in which our business is managed and our resources are allocated. Following the consummation of the NIPSCO Minority Interest Transaction, we revised how we evaluate results and allocate resources across our business with an increased focus on operating performance at the state level. Refer to Note 4, "Noncontrolling Interests," for additional information on the NIPSCO Minority Interest Transaction. At December 31, 2025, our operations are divided into two primary reportable segments, the Columbia Operations and the NIPSCO Operations segments. Columbia Operations aggregates the results of the fully regulated and wholly owned subsidiaries of 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). Each Columbia distribution company is an operating segment which we aggregate to form the Columbia Operations reportable segment. NIPSCO Operations includes the results of NIPSCO Holdings I and its majority-owned subsidiaries, including NIPSCO, which has fully regulated gas and electric operations in northern Indiana. Our historical segment disclosures have been recast to be consistent with the current presentation.The remainder of our operations, which are not significant enough on a stand-alone basis to warrant treatment as an operating segment, are presented as "Corporate and Other" in the subsequent reconciliation table and primarily are comprised of interest expense on holding company debt and unallocated corporate costs and activities, as well as new business development costs associated with GenCo. Refer to Note 3, "Revenue Recognition," for additional information on our segments and their sources of revenues. The following table provides information about our reportable segments. We use operating income as our primary measurement for each of the reported segments and make decisions on financing, dividends and taxes at the corporate level on a consolidated basis. We provide this measure to our Chief Operating Decision Maker, the CEO, who utilizes this measure to make operating segment level strategy decisions based on budget-to-actual variances and against prior periods to allocate resources accordingly. Segment revenues include intersegment sales to affiliated subsidiaries, which are eliminated in consolidation.

Customer Revenues. Substantially all of our revenues are tariff-based. Under ASC 606, the recipients of our utility service meet the definition of a customer, while the operating company tariffs represent an agreement that meets the definition of a contract, which creates enforceable rights and obligations. Customers in certain of our jurisdictions participate in programs that allow for a fixed payment each month regardless of usage. Payments received that exceed the value of gas or electricity actually delivered are recorded as a liability and presented in "Customer deposits and credits" on the Consolidated Balance Sheets. Amounts in this account are reduced and revenue is recorded when customer usage exceeds payments received.We have identified our performance obligations created under tariff-based sales as i) the commodity (natural gas or electricity, which includes generation and capacity) and ii) delivery. These commodities are sold and / or delivered to and generally consumed by customers simultaneously, leading to satisfaction of our performance obligations over time as gas or electricity is delivered to customers. Due to the at-will nature of utility customers, performance obligations are limited to the services requested and received to date. Once complete, we generally maintain no additional performance obligations.Transaction prices for each performance obligation are generally prescribed by each operating company’s respective tariff. Rates include provisions to adjust billings for fluctuations in fuel and purchased power costs and cost of natural gas. Revenues are adjusted for differences between actual costs, subject to reconciliation, and the amounts billed in current rates. Under or over recovered revenues related to these cost recovery mechanisms are included in "Regulatory assets" or "Regulatory liabilities" on the Consolidated Balance Sheets and are recovered from or returned to customers through adjustments to tariff rates. As we provide and deliver service to customers, revenue is recognized based on the transaction price allocated to each performance obligation. Distribution revenues are generally considered daily or "at-will" contracts as customers may cancel their service at any time (subject to notification requirements), and revenue generally represents the amount we are entitled to bill customers.

Contractual Obligations. We have certain contractual obligations requiring payments at specified periods. The obligations include long-term debt, lease obligations, energy commodity contracts and obligations for various services including pipeline capacity and outsourcing of IT services. The total contractual obligations in existence at December 31, 2025 and their maturities were:(in millions)Total20262027202820292030AfterLong-term debt (1)$15,345.0 $— $1,090.0 $1,055.0 $1,350.0 $1,000.0 $10,850.0 Interest payments on long-term debt12,361.2 729.1 725.1 675.0 647.3 575.9 9,008.8 Finance leases(2)497.9 32.6 27.4 26.2 21.3 22.3 368.1 Operating leases(3)30.5 10.7 5.1 3.8 3.2 2.1 5.6 Energy commodity and capacity contracts476.9 315.9 116.7 9.3 7.6 4.6 22.8 Service obligations:Pipeline service obligations2,829.1 809.5 879.3 482.3 326.5 156.6 174.9 IT service obligations322.1 98.3 81.8 61.7 43.0 37.3 — Plant equipment purchase obligations103.3 87.6 10.4 5.3 — — — Other liabilities(4)120.3 74.0 10.1 9.5 8.4 8.0 10.3 Total contractual obligations$32,086.3 $2,157.7 $2,945.9 $2,328.1 $2,407.3 $1,806.8 $20,440.5 (1) Long-term debt balance excludes unamortized issuance costs and discounts of $141.5 million and finance leases of $274.0 million. (2) Finance lease payments shown above are inclusive of interest totaling $223.9 million. (3) Operating lease payments shown above are inclusive of interest totaling $3.6 million. Operating lease balances do not include obligations for possible fleet vehicle lease renewals beyond the initial lease term. While we have the ability to renew these leases beyond the initial term, we are not reasonably certain to do so as they are renewed month-to-month after the first year. (4)Other liabilities shown above are primarily related to the current EPC contract and ongoing maintenance service agreements for our renewable joint ventures.Purchase and Service Obligations. We have entered into various purchase and service agreements whereby we are contractually obligated to make certain minimum payments in future periods. Our energy commodity contracts are for the purchase of physical quantities of natural gas, electricity, coal and purchases of electric capacity. Our service obligations, consisting of pipeline service obligations and IT service obligations, encompass a broad range of business support and maintenance functions which are generally described below.

Our long-term debt as of December 31, 2025 and 2024 is as follows:Long-term debt type Maturity as of December 31, 2025Weighted average interest rate (%)Outstanding balance as of December 31, (in millions)20252024Senior notes: NiSourceAugust 20250.950 %$— $1,250.0 NiSourceMay 20273.490 %1,000.0 1,000.0 NiSourceDecember 20276.780 %3.0 3.0 NiSourceMarch 20285.250 %1,050.0 1,050.0 NiSourceJuly 20295.200 %600.0 600.0 NiSourceSeptember 20292.950 %750.0 750.0 NiSourceMay 20303.600 %1,000.0 1,000.0 NiSourceFebruary 20311.700 %750.0 750.0 NiSourceJune 20335.400 %450.0 450.0 NiSourceApril 20345.350 %650.0 650.0 NiSourceJuly 20355.350 %900.0 — NiSourceDecember 20406.250 %152.6 152.6 NiSourceJune 20415.950 %347.4 347.4 NiSourceFebruary 20425.800 %250.0 250.0 NiSourceFebruary 20435.250 %500.0 500.0 NiSourceFebruary 20444.800 %750.0 750.0 NiSourceFebruary 20455.650 %500.0 500.0 NiSourceMay 20474.375 %1,000.0 1,000.0 NiSourceMarch 20483.950 %750.0 750.0 NiSourceJune 20525.000 %350.0 350.0 NiSourceApril 20555.850 %1,500.0 — Total senior notes$13,253.0 $12,103.0 Junior subordinated notes:NiSourceNovember 20546.950 %$500.0 $500.0 NiSourceMarch 20556.375 %500.0 500.0 NiSourceJuly 20565.750 %1,000.0 — Total junior subordinated notes$2,000.0 $1,000.0 Medium term notes:NiSourceMay 20277.990 %$29.0 $29.0 NIPSCOJune 2027 to August 20277.644 %58.0 58.0 Columbia of MassachusettsDecember 20256.430 %— 10.0 Columbia of MassachusettsFebruary 20286.260 %5.0 5.0 Total medium term notes$92.0 $102.0 Finance leases:NiSource Corporate ServicesJanuary 2026 to September 20274.350 %$5.0 $14.6 NIPSCODecember 2027 to December 20635.480 %165.5 124.3 Columbia of OhioDecember 2035 to March 20526.110 %81.7 85.6 Columbia of VirginiaJuly 2029 to November 20395.620 %16.2 15.2 Columbia of KentuckyMay 20275.360 %0.1 0.1 Columbia of PennsylvaniaMarch 2030 to May 20354.430 %5.5 6.4 Total finance leases$274.0 $246.2 Less: Unamortized issuance costs and discounts(141.5)(95.5)Less: Current portion of long term debt(19.7)(1,281.2)Total Long-Term Debt$15,457.8 $12,074.5 Details of our 2025 long-term debt activity are summarized below:•In March 2025, we completed the issuance and sale of $750.0 million of 5.850% senior unsecured notes maturing in 2055, which resulted in approximately $739.6 million of net proceeds after discount and debt issuance costs. •In June 2025, we completed the issuance and sale of an additional $750.0 million of 5.850% senior unsecured notes maturing in 2055 (the "2055 Notes").

Judgment and the use of estimates are required in developing the provision for income taxes and reporting of tax-related assets and liabilities. The interpretation of tax laws and associated regulations involves uncertainty as taxing authorities may interpret the laws differently.NIPSCO’s historical business activities through the closing of the NIPSCO Minority Interest Transaction in 2023 were included in the consolidated U.S. federal and certain state income tax returns of NiSource Inc. Prior to April 13, 2023, NIPSCO was treated as a taxable division of its corporate parent, NiSource Inc. Beginning on that date, NIPSCO became a division of NIPSCO Holdings I. In connection with the NIPSCO Minority Interest Transaction, NIPSCO Holdings I retained NIPSCO’s income tax balances and 80.1% of the excess deferred income tax regulatory balances as described below. NIPSCO Holdings I’s income tax balances are based on the difference between the financial statement amount and the tax basis of its investment in NIPSCO Holdings II.Income Tax Expense. The components of income tax expense (benefit) were as follows: Year Ended December 31, (in millions)202520242023Income TaxesCurrentFederal$(30.4)$(19.3)$— State(1.6)9.4 5.3 Total Current (Benefit) Expense(32.0)(9.9)5.3 DeferredFederalTaxes before operating loss carryforwards and investment credits189.2 105.9 49.7 Tax utilization expense of operating loss carryforwards34.2 60.4 65.1 Investment tax credits— (0.1)(2.1)State13.1 2.6 22.5 Total Deferred Expense236.5 168.8 135.2 Deferred Investment Tax Credits(0.7)(0.8)(1.0)Income Taxes from Continuing Operations$203.8 $158.1 $139.5 We earn federal Investment Tax Credits ("ITC"s) and Production Tax Credits ("PTC"s) related to qualifying renewable energy projects. These credits are nonrefundable, can be utilized to offset income tax liabilities, and are transferable. We recognize the benefit of these credits within income tax expense (benefit) in the period the credits are generated.During the periods ended December 31, 2025 and 2024, respectively, we elected to monetize certain transferable ITC/PTC credits through sales to unrelated third‑party taxpayers. Accordingly, the cash proceeds received from the sale of the credits are reflected as an adjustment to income tax (benefit) expense. We recognized a current tax benefit associated with the monetization of these credits of $19.3 million and $18.8 million, for the years ended December 31, 2025, and 2024, respectively.

Lease Descriptions. We are the lessee for substantially all of our leasing activity, which includes operating and finance leases for corporate and field offices, railcars, land, and fleet vehicles. Our corporate and field office leases and certain land leases have remaining terms between 1 and 38 years with options to renew the leases for up to 35 years. We lease railcars to transport coal to and from our electric generation facilities in Indiana. Our railcars are specifically identified in the lease agreements which have remaining lease terms between 1 and 3 years with options to renew for 1 year. Our fleet vehicles include trucks, trailers and equipment that have been customized specifically for use in the utility industry. We lease fleet vehicles for 1 year terms, after which we have the option to extend on a month-to-month basis or terminate with written notice. We elected the short-term lease practical expedient, allowing us to not recognize ROU assets or lease liabilities for all leases with a term of 12 months or less. ROU assets and liabilities on our Consolidated Balance Sheets do not include obligations for possible fleet vehicle lease renewals beyond the initial lease term. While we have the ability to renew these leases beyond the initial term, we are not reasonably certain to do so. We have not provided material residual value guarantees for our leases, nor do our leases contain material restrictions or covenants. Lease contracts containing renewal and termination options are mostly exercisable at our sole discretion. Certain of our real estate and railcar leases include renewal periods in the measurement of the lease obligation if we have deemed the renewals reasonably certain to be exercised.With respect to service contracts involving the use of assets, if we have the right to direct the use of the asset and obtain substantially all economic benefits from the use of an asset, we account for the service contract as a lease. Unless specifically provided to us by the lessor, we utilize NiSource's collateralized incremental borrowing rate commensurate to the lease term as the discount rate for all of our leases. ASC 842 permits a lessee, by class of underlying asset, not to separate nonlease components from lease components. Our policy is to apply this expedient for our leases of fleet vehicles, IT assets and railcars when calculating their respective lease liabilities.

We have implemented and maintain a comprehensive cybersecurity program that includes a variety of security controls and measures designed to identify, assess, and manage material cybersecurity risks. The program is a part of our enterprise risk management strategy. The enterprise risk team and the Risk Management Committee review material risks to any NiSource operating company based on perspectives from external experts, peer surveys, and the potential impact to our enterprise assets and strategic objectives.Risk events are classified based on both the timing of impact and NiSource’s ability to preventatively mitigate the risk. For the cybersecurity risks that can be preventively mitigated, the enterprise risk team gathers quarterly updates on mitigation gap closure from risk owners. The Risk Management Committee reviews any mitigation gaps identified by risk owners and approves or rejects the pace of mitigation activities as a statement of risk tolerance and then directs that mitigation activities be included in budgets and the business plan as appropriate. Our cybersecurity program includes the following key components:Risk assessment. We regularly assess our cybersecurity risks to identify and prioritize the most significant threats. The risk assessment process considers a variety of factors, including those specific to the utility/energy industry, the types of data we collect and store, and the threats posed by known vulnerabilities. We engage third parties to perform independent assessments of our cybersecurity program, provide intelligence about the threat environment, and to provide operational assistance in managing the program. Annually, a third-party independent assessment is performed to evaluate our cybersecurity maturity against a framework of cybersecurity controls. We also perform bi-annual penetration testing and social engineering assessments performed by a third-party.Third-party risk management. We perform cyber assessments periodically on all third-party vendors and service providers with whom we share data, rely on for critical business functions, or provide access to our network or systems. Our Supply Chain function works with the Legal and Cyber functions to periodically update cybersecurity contractual provisions in its vendor agreements, with deviations from such provisions requiring approval from the Legal and Cyber functions.

Holders of shares of our common stock are entitled to receive dividends when, as, and if declared by the Board out of funds legally available. The policy of the Board has been to declare cash dividends on a quarterly basis payable on or about the 20th day of February, May, August and November. We have certain debt covenants that could restrict our ability to pay dividends or potentially limit the amount of dividends we could pay in order to maintain compliance with these covenants. Refer to Note 8, "Long-Term Debt," for more information. As of December 31, 2025, these covenants did not restrict our ability to pay dividends or the amount of dividends that were available to be paid. There is no preferred stock outstanding as of December 31, 2025. Common and preferred stock activity for 2025, 2024 and 2023 is described further below.Details of our 2024 ATM program are summarized below:•In February 2024, we entered into eight separate equity distribution agreements providing for the sale of up to an aggregate of $900.0 million of our common stock. •During 2024, we executed and settled four forward sale agreements. Under these agreements, we issued 21,143,900 shares resulting in net proceeds of $600.3 million. •In February 2025, we executed a forward sale agreement, which allowed us to issue a fixed number of shares at a price to be settled in the future. The forward purchaser under our forward sale agreement borrowed 2,000,000 shares from third parties, which the forward purchaser sold, through its affiliated agent, at a weighted average price of $40.10 per share. In September 2025, we settled the forward sale agreement in shares for $80.0 million, based on a net price of $40.02 per share. •In March 2025, we executed a forward sale agreement, which allowed us to issue a fixed number of shares at a price to be settled in the future. The forward purchaser under our forward sale agreement borrowed 1,707,320 shares from third parties, which the forward purchaser sold, through its affiliated agent, at a weighted average price of $41.00 per share. In September 2025, we settled the forward sale agreement in shares for $69.9 million, based on a net price of $40.92 per share. •In June 2025, we executed a forward sale agreement, which allowed us to issue a fixed number of shares at a price to be settled in the future.