NorthWestern Energy Group, Inc.

NorthWestern Energy Group, doing business as NorthWestern Energy, provides essential energy infrastructure and services. The company delivers electricity and/or natural gas to approximately 850,300 customers across Montana, South Dakota, Nebraska, and Yellowstone National Park. Operations in Montana and Yellowstone National Park are conducted through its subsidiary, NW Corp. Operations in South Dakota and Nebraska are conducted through its subsidiary, NWE Public Service. NorthWestern Energy has provided service in South Dakota and Nebraska since 1923 and in Montana since 2002. In 2023, NW Corp became a subsidiary of NorthWestern Energy Group following a holding company reorganization. On August 18, 2025, NorthWestern Energy entered into a Merger Agreement with Black Hills and Merger Sub. This agreement outlines an all-stock merger of equals, where Merger Sub will merge into NorthWestern, with NorthWestern continuing as the surviving entity and a direct wholly owned subsidiary of Black Hills. Black Hills would then assume the new corporate name of Bright Horizon Energy as the parent company. At the effective time of the Merger, each outstanding share of NorthWestern common stock will be converted into the right to receive 0.98 shares of Black Hills common stock, par value $1.00 per share.