Black Hills Corp. (NYSE: BKH) and NorthWestern Energy Group, Inc. (d/b/a NorthWestern Energy) (Nasdaq: NWE) have announced that each company’s board of directors has unanimously approved a definitive agreement to combine in an all-stock, tax-free merger that will create a premier regional regulated electric and natural gas utility company with a pro forma market capitalization of approximately $7.8 billion and a combined enterprise value of $15.4 billion, based on each company’s closing stock price as of August 18, 2025.
Milbank LLP is advising Greenhill & Co., a Mizuho affiliate serving as exclusive financial advisor to NorthWestern, in connection with the transaction.
The transaction is expected to close in 12 to 15 months, subject to customary closing conditions. The combined company will serve approximately 2.1 million customers across Arkansas, Colorado, Iowa, Kansas, Montana, Nebraska, South Dakota and Wyoming.
The Milbank team advising Greenhill is led by Global Corporate/M&A partners Iliana Ongun and Scott Golenbock with associate Katerina Dvalishvili.
