FOR ADDITIONAL INFORMATION (Form 8-K)

FOR ADDITIONAL INFORMATION

Media Investors

[email protected] [email protected]

NiSource announces third quarter results

•Narrowing 2026 non-GAAP consolidated adjusted EPS guidance to upper half of $2.02-$2.07 range

•Introducing 2027 non-GAAP consolidated adjusted EPS guidance

•Extending base plan expected non-GAAP adjusted EPS annual growth guidance of 6%-8% to 2027-2033

•Raising consolidated expected non-GAAP adjusted EPS compound annual growth rate to 10%-11% for 2027-2033

•Expanding GenCo cost savings for existing customers to approximately $1.75 billion through new agreement with Microsoft

MERRILLVILLE, Ind. - NiSource Inc. (NYSE: NI) today announced, on a GAAP basis, net income available to common shareholders for the quarter ended September 30, 2026 of $129.5 million, or $0.27 of earnings per diluted share, compared to net income available to common shareholders of $94.7 million, or $0.20 of earnings per diluted share, for the same period of 2025. For the nine months ended September 30, 2026, on a GAAP basis, NiSource's net income available to common shareholders was $685.7 million, or $1.42 of diluted earnings per share, compared to net income available to common shareholders of $671.7 million, or $1.42 of diluted earnings per share, for the same period of 2025.

NiSource also reported third quarter 2026 non-GAAP adjusted net income available to common shareholders of $130.9 million, or $0.27 of consolidated adjusted EPS, compared to non-GAAP adjusted net income available to common shareholders of $91.8 million, or $0.19 of consolidated adjusted EPS, for the same period of 2025. For the nine months ended September  30, 2026, NiSource's non-GAAP adjusted net income available to common shareholders was $718.1 million, or $1.49 of consolidated adjusted EPS, compared to non-GAAP adjusted net income available to common shareholders of $656.0 million, or $1.38 of consolidated adjusted EPS, for the same period of 2025. Schedule 1 of this press release contains a complete reconciliation of GAAP measures to non-GAAP measures. **

NiSource is narrowing its 2026 non-GAAP consolidated adjusted EPS guidance to the upper half of $2.02-$2.07. In 2027, non-GAAP consolidated adjusted EPS is expected to be in the range of $2.22-$2.30.

NiSource is extending its capital plan through 2033. The new consolidated seven-year total capital expenditures of $40.0 billion are expected to support 9%-10% consolidated investment base growth from 2027-2033 and an expected consolidated non-GAAP adjusted EPS compound annual growth rate (CAGR) of 10%-11% for 2027-2033. The company's base plan non-GAAP adjusted EPS growth is expected to be 6%-8% annually with 8%-10% rate base growth expected from 2027-2033.

1

The consolidated capital expenditure plan is driven by $32.0 billion in base plan capital expenditures and $8.0 billion for data center investments for 2027-2033.

"The extension of our long-term plan reflects the significant opportunities ahead for NiSource and our confidence in our ability to deliver," said Lloyd Yates, President and Chief Executive Officer of NiSource. "Our seven-year capital plan supports critical infrastructure investments to enhance the safety, reliability, and resiliency of our systems while enabling significant economic development across our footprint."

"This year's extreme weather events have reinforced the importance of those investments, while opportunities such as Microsoft and our GenCo pipeline further strengthen the outlook. Our signed GenCo agreements are expected to deliver approximately $1.75 billion in customer savings, positioning us to deliver industry-leading growth and long-term value for customers, communities, and shareholders.

"I also want to thank our employees for their dedication to serving customers and restoring service during severe weather events. Their commitment, along with the support of our regulators, policymakers, customers, investors, and community partners, positions us well to execute this plan and deliver sustainable value for all stakeholders."

2

**Non-GAAP Disclosure Statement