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BUTTE, MT / SIOUX FALLS, SD - February 11, 2026 - NorthWestern Energy Group, Inc. d/b/a NorthWestern Energy (Nasdaq: NWE) reported financial results for the year ended December 31, 2025. Net income for the period was $181.1 million, or $2.94 per diluted share, as compared with net income of $224.1 million, or $3.65 per diluted share, for the same period in 2024. This decrease was primarily due to higher operating expenses, including a non-cash charge for the regulatory disallowance of certain Yellowstone County Generating Station (YCGS) capital costs, merger-related costs, and depreciation, interest expense, Montana property tax tracker collections, non-recoverable Montana electric supply costs, and higher income tax expense. These were partly offset by higher rates, electric transmission revenue, natural gas transportation revenues, and retail volumes.

NorthWestern's 2025 non-GAAP net income and earnings per share were $220.1 million and $3.58, respectively, compared to $208.9 million and $3.40 in 2024. See “Adjusted Non-GAAP Earnings” and “Non- GAAP Financial Measures” sections below for more information on these measures.

“We are pleased to report on what has been an exceptionally busy and transformational year for NorthWestern” said Brian Bird, President and Chief Executive Officer. "Throughout 2025, we advanced several major initiatives to support safe, reliable, and affordable service for our customers across Montana, South Dakota, and Nebraska. In Montana, the passage of House Bill 490 was a critical achievement, providing clarity and limits around wildfire-related risks and offering greater certainty for our customers, communities, and investors. We also completed the Energy West acquisition, welcoming roughly 33,000 new natural gas customers to our system. In addition, we completed our Montana electric and natural gas rate review in December, receiving recovery of the significant investments we made to reliably serve our customers and incorporating the Yellowstone County Generating Station into rates — an asset that had already been delivering value to customers since the start of 2025.”

“The year also marked important steps forward in our long-term strategic vision. We announced our merger agreement with Black Hills Corporation in August, a combination that will create a stronger, more resilient utility better positioned for the future. Together, we have filed applications with regulators in Montana, South Dakota, Nebraska, and FERC, targeting a close in the back half of 2026. We also completed the acquisition of the Avista and Puget Colstrip interests on January 1, 2026—a timely and strategic transaction that advances resource adequacy, protects our ability to serve our Montana customers reliably and affordably, and supports the potential integration of large-load customers, delivering long-term benefits for our customers, communities, and investors. Our progress this year reflects the dedication of our exceptional employees and the trust of the customers and communities we proudly serve, and as we move into another year of strong execution, we remain committed to providing safe, reliable, and affordable energy while advancing long-term value for our shareholders,” said Bird.

NorthWestern Energy Group, Inc., doing business as NorthWestern Energy, provides essential energy infrastructure and valuable services that enrich lives and empower communities while serving as long-term partners to our customers and communities. We work to deliver safe, reliable, and innovative energy solutions that create value for customers, communities, employees, and investors. We do this by providing low-cost and reliable service performed by highly-adaptable and skilled employees. We provide electricity and / or natural gas to approximately 842,100 customers in Montana, South Dakota, Nebraska, and Yellowstone National Park. Our operations in Montana and Yellowstone National Park are conducted through our subsidiary, NW Corp, and our operations in South Dakota and Nebraska are conducted through our subsidiary, NWE Public Service. We have provided service in South Dakota and Nebraska since 1923 and in Montana since 2002.