Black Hills Corp. (NYSE: BKH) and NorthWestern Energy Group, Inc. (Nasdaq: NWE) said their boards of directors have unanimously approved a definitive agreement to combine in an all-stock, tax-free merger. The deal will create a regulated electric and natural gas utility company with an estimated market capitalization of $7.8 billion and an enterprise value of $15.4 billion, based on both companies’ closing stock prices on August 18, 2025.
Under the terms of the agreement, NorthWestern shareholders will receive 0.98 shares of Black Hills common stock for each share of NorthWestern they own. The exchange ratio reflects an approximate 2% to 4% premium compared to the companies’ average stock prices since they began discussing terms in March. Following the merger, Black Hills shareholders will own about 56% of the combined company, with NorthWestern shareholders holding approximately 44%.
The merged utility will be headquartered in Rapid City, South Dakota, while maintaining operational and leadership offices across its service territories. The company will adopt a new name and ticker symbol before the deal closes, but both Black Hills and NorthWestern will continue operating under their current names immediately after the transaction.
Leadership of the combined entity will include Brian Bird, currently President and CEO of NorthWestern, as Chief Executive Officer. Marne Jones of Black Hills will serve as Chief Operating Officer, Crystal Lail of NorthWestern as Chief Financial Officer, and Kimberly Nooney of Black Hills as Chief Integration Officer. Black Hills President and CEO Linn Evans will remain in his role until closing, after which he plans to retire.
The combined board of directors will consist of 11 members: six designated by Black Hills and five by NorthWestern, including Bird and NorthWestern board chair Linda Sullivan. Steven Mills, chair of the Black Hills board, will serve as chair of the new company’s board.
Advisors on the transaction include Goldman Sachs & Co. LLC and Faegre Drinker Biddle & Reath LLP for Black Hills, and Greenhill, a Mizuho affiliate, along with Morgan, Lewis & Bockius LLP for NorthWestern.
The merger is subject to approval by shareholders of both companies, as well as regulatory clearances.
Several law firms, including Halper Sadeh LLC and Kahn Swick & Foti, LLC, have announced investigations into whether the transaction terms adequately protect the interests of NorthWestern shareholders.