BLACK HILLS CORP /SD/ 8-K

What Happened
Black Hills Corporation filed a Current Report on Form 8‑K on May 15, 2026 to provide information about its pending all‑stock merger with NorthWestern Energy Group, Inc. The parties entered an Agreement and Plan of Merger on August 18, 2025 (unanimously approved by both companies' boards) under which River Merger Sub Inc., a Black Hills subsidiary, will be used to effect the combination. The merger remains subject to customary closing conditions, including approvals from certain state regulatory commissions and the Federal Energy Regulatory Commission (FERC).

Key Details

• Merger agreement signed and unanimously approved by both boards on August 18, 2025.
• Transaction structure: all‑stock business combination involving River Merger Sub Inc., a wholly owned Black Hills subsidiary.
• 8‑K filed May 15, 2026 includes Exhibit 99.1 (unaudited consolidated financials of NorthWestern for the three months ended March 31, 2026 and 2025) and Exhibit 99.2 (unaudited pro forma condensed combined financial statements for the three months ended March 31, 2026 and for the year ended December 31, 2025).
• Report signed by Kimberly F. Nooney, Senior Vice President and Chief Financial Officer, on behalf of Black Hills.

Why It Matters
This filing gives investors more detailed financial information about NorthWestern and pro forma results for the combined companies, which helps assess the deal’s financial implications. The transaction is still conditional on regulatory approvals (including state commissions and FERC), so timing and completion remain uncertain until those approvals and other conditions are satisfied.