NiSource 10-Q 2026-06-30

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-Q

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

OF THE SECURITIES EXCHANGE ACT OF 1934

For the quarterly period ended June 30, 2026

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)

(614) 460-6000

(Registrant’s telephone number, including area code)

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

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 definitions of "large accelerated filer," "accelerated filer," "smaller reporting company," and "emerging growth company" in Rule 12b-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 is a shell company (as defined in Rule 12b-2 of the Exchange Act).

Yes ☐ No ☑

Indicate the number of shares outstanding of each of the issuer’s classes of common stock, as of the latest practicable date: Common Stock, $0.01 Par Value: 479,560,100 shares outstanding at July 29, 2026.

NISOURCE INC.

FORM 10-Q QUARTERLY REPORT

FOR THE QUARTER ENDED JUNE 30, 2026

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NiSource Inc.

Notes to Condensed Consolidated Financial Statements (unaudited) (continued)

an analysis to determine whether the unrealized loss is related to credit factors. The analysis focuses on a variety of factors that include, but are not limited to, downgrade on ratings of the security, defaults in the current reporting period or projected defaults in the future, the security's yield spread over treasuries, and other relevant market data. If the unrealized loss is not related to credit factors, it is included in other comprehensive income. If the unrealized loss is related to credit factors, the loss is recognized as credit loss expense in earnings during the period, with an offsetting entry to the allowance for credit losses. The amount of the credit loss recorded to the allowance account is limited by the amount at which the security's fair value is less than its amortized cost basis. If certain amounts recorded in the allowance for credit losses are deemed uncollectible, the allowance on the uncollectible portion will be charged off, with an offsetting entry to the carrying value of the security. Subsequent improvements to the estimated credit losses of available-for-sale debt securities will be recognized immediately in earnings. Continuous credit monitoring and portfolio credit balancing mitigates our risk of credit losses on our available-for-sale debt securities.

The amortized cost, gross unrealized gains and losses, allowance for credit losses, and fair value of available-for-sale securities at June 30, 2026 and December 31, 2025 were:

(1)Fair value of U.S. Treasury debt securities and Corporate/Other debt securities in an unrealized loss position without an allowance for credit losses is $8.7 million and $74.2 million, respectively, at June 30, 2026.

(2)Fair value of U.S. Treasury debt securities and Corporate/Other debt securities in an unrealized loss position without an allowance for credit losses is $3.5 million and $40.2 million, respectively, at December 31, 2025.

The cost of maturities sold is based upon specific identification. Net realized gains and losses on available-for-sale securities were $0.1 million for the three and six months ended June 30, 2026 and 2025, respectively. At June 30, 2026, approximately $10.6 million and $5.8 million of Corporate/Other debt securities and U.S. Treasury debt securities, respectively, had maturities of less than a year.

Equity Investments. Investments measured at net asset value per share (or its equivalent) as a practical expedient have not been classified in the fair value hierarchy. These investments represent holdings in a single private investment fund that are redeemable at the election of the holder. As of June 30, 2026 and December 31, 2025, the Company holds $18.4 million and $17.9 million of equity investments measured at net asset value, respectively.

Non-recurring Fair Value Measurements

We measure the fair value of certain assets, including goodwill, on a non-recurring basis, typically when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. As of June 30, 2026, no non-recurring fair value adjustments have been made.

B. Other Fair Value Disclosures for Financial Instruments. The carrying amount of cash and cash equivalents, restricted cash, notes receivable, customer deposits and short-term borrowings is a reasonable estimate of fair value due to their liquid or short-term nature. Our long-term borrowings are recorded at historical amounts.

The following method and assumptions were used to estimate the fair value of each class of financial instruments.

Long-term Debt. The fair value of outstanding long-term debt is estimated based on the quoted market prices for the same or similar securities. Certain premium costs associated with the early settlement of long-term debt are not taken into consideration in determining fair value. These fair value measurements are classified within Level 2 of the fair value hierarchy. As of June 30, 2026, there was no change in the method or significant assumptions used to estimate the fair value of long-term debt.

The carrying amount and estimated fair values of these financial instruments were as follows:

12. Goodwill

The following presents our goodwill balance allocated by segment as of June 30, 2026:

For our annual goodwill impairment analysis performed as of May 1, 2026, we performed a qualitative "step 0" assessment and determined that it was more likely than not that the estimated fair value of the reporting units substantially exceeded their carrying values. For this test, we assessed various assumptions, events and circumstances that would have affected the estimated fair value of the reporting units as compared to their baseline May 1, 2024 "step 1" fair value measurement. There have been no impairments recorded during the periods presented.

**13.

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NiSource Inc.

NIPSCO Operations

Financial and operational data for the NIPSCO Operations segment, which services both gas and electric customers, for the three and six months ended June 30, 2026 and 2025 are presented below.

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Quantitative and qualitative disclosures about market risk are reported in Item 2, "Management's Discussion and Analysis of Financial Condition and Results of Operations - Market Risk Disclosures."

Evaluation of Disclosure Controls and Procedures

Our chief executive officer and our chief financial officer are responsible for evaluating the effectiveness of our disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)). Our disclosure controls and procedures are designed to provide reasonable assurance that the information required to be disclosed by us in reports that we file or submit under the Exchange Act is accumulated and communicated to our management, including our chief executive officer and chief financial officer, as appropriate, to allow timely decisions regarding required disclosure and is recorded, processed, summarized and reported within the time periods specified in the rules and forms of the SEC. Based upon that evaluation, our chief executive officer and chief financial officer concluded that, as of the end of the period covered by this report, our disclosure controls and procedures were effective at a reasonable assurance level.

Changes in Internal Controls

There have been no changes in our internal control over financial reporting during the most recently completed quarter covered by this report that have materially affected, are reasonably likely to materially affect, our internal control over financial reporting.

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NiSource Inc.

PART II

ITEM 1. LEGAL PROCEEDINGS

For a description of our legal proceedings, see Note 15, "Other Commitments and Contingencies - B. Legal Proceedings," in the Notes to the Condensed Consolidated Financial Statements (unaudited).

Please refer to the risk factors set forth in Part I, Item 1A of the Annual Report on Form 10-K for the year ended December 31, 2025. There have been no material changes to such risk factors.

ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS

None.

ITEM 3. DEFAULTS UPON SENIOR SECURITIES

None.

ITEM 4. MINE SAFETY DISCLOSURES

Not applicable.

Director and Officer Trading Arrangements

The following table describes any contracts, instructions or written plans for the sale or purchase of NiSource securities that are intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) of the Exchange Act that were adopted by our directors and executive officers during the quarter ended June 30, 2026:

(1) A trading plan may also expire on such earlier date that all transactions under the trading plan are completed.

(2) Aggregate number may increase upon time of transacting in order to account for dividends.

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NiSource Inc.

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SIGNATURE

NiSource Inc.

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.