Subject to Receipt of Satisfactory Final Regulatory Approval and Completion of Proposed Merger, Black Hills Corp. to be Renamed Bright Horizon Energy Corporation with Ticker Symbol “HZN”

* The Montana Public Service Commission is expected to consider the merger prior to Nov. 12, 2026, and completion remains subject to satisfactory final regulatory approval by the Commission. * Trading under new company name and ticker symbol is only expected upon completion of the merger. RAPID CITY, S.D. and BUTTE, Mont. and SIOUX FALLS, S.D., Oct. 22, 2026 (GLOBE NEWSWIRE) -- Black Hills Corp. (NYSE: BKH) and NorthWestern Energy Group, Inc. d/b/a NorthWestern Energy (Nasdaq: NWE) today announced plans for the name and ticker symbol of the combined company in the event their proposed merger receives final, satisfactory regulatory approval and is completed. If the proposed merger is approved and completed, Black Hills Corp. will be renamed Bright Horizon Energy Corporation (“Bright Horizon Energy”), its common stock will trade on the New York Stock Exchange (NYSE) under the ticker symbol “HZN,” and NorthWestern Energy will become a wholly owned subsidiary of Bright Horizon Energy.