Black Hills Corporation (BKH) enters into all-stock merger agreement with NorthWestern Energy Group

On August 18, 2025, prior to the execution of the Merger Agreement, the Black Hills Board adopted an amendment to Black Hills’ bylaws (the “ Bylaw Amendment ”). The Bylaw Amendment removes the age limit for directors as previously provided in Section 3. A modified retirement age provision was added to Black Hills’ Corporate Governance Guidelines at the same time. The Bylaw Amendment also adds a new Article X, which provides that, unless Black Hills consents in writing to the selection of an alternative forum, the federal and state courts located in Pennington County, South Dakota shall be the sole and exclusive forum for certain specified corporate-law based suits involving Black Hills. The Bylaw Amendment also provides for federal district court to be the sole and exclusive forum for the resolution of complaints arising under the Securities Act of 1933.