NISOURCE INC

13. Income Taxes

Our interim effective tax rates reflect the estimated annual effective tax rates for 2024 and 2023 applied to year-to-date pretax income, adjusted for tax expense associated with certain discrete items. The effective tax rates for the three months ended March 31, 2024 and 2023 were 16.0% and 20.3%, respectively. These effective tax rates differ from the federal statutory tax rate of 21% primarily due to renewable partnership income, amortization of excess deferred federal income tax liabilities, as specified in the TCJA, tax credits, state flow through, and other permanent book-to-tax differences.

The decrease in the three month effective tax rate of 4.3% in 2024 compared to 2023 is primarily attributed to the lower renewable partnership income, jurisdictional mix of pre-tax book income, offset by lower amortization of excess deferred federal income tax liabilities.

As of March 31, 2024, there have been no material changes to our unrecognized tax benefits or possible changes that could reasonably be expected to occur during the next twelve months. See Note 15 to the Company’s Consolidated Financial Statements in the Annual Report on Form 10-K for the year ended December 31, 2023, for a discussion of these unrecognized tax benefits.