BLACK HILLS CORP /SD/

Black Hills Corporation, a South Dakota corporation (together with its subsidiaries, referred to herein as the “Company,” "BHC," “we,” “us”, or “our”), is a customer-focused, growth-oriented utility company headquartered in Rapid City, South Dakota (incorporated in South Dakota in 1941).

We operate our business in the United States, reporting our operating results through our Electric Utilities and Gas Utilities segments. Certain unallocated corporate expenses that support our operating segments are presented as Corporate and Other.

Our Electric Utilities segment generates, transmits and distributes electricity to approximately 227,000 electric utility customers in Colorado, Montana, South Dakota, and Wyoming. Our Electric Utilities own 1,386 MW of generation and 9,478 miles of electric transmission and distribution lines.

Our Gas Utilities segment serves approximately 1,138,000 natural gas utility customers in Arkansas, Colorado, Iowa, Kansas, Nebraska, and Wyoming. Our Gas Utilities own and operate 4,581 miles of intrastate gas transmission pipelines and 44,840 miles of gas distribution mains and service lines, seven natural gas storage sites, more than 50,000 horsepower of compression, and 494 miles of gathering lines.

Proposed Merger with NorthWestern

BHC and NorthWestern entered into an all-stock business combination on August 18, 2025. The transaction is intended to be tax-free and expected to close in the second half of 2026, subject to the satisfaction or waiver of certain closing conditions, including approvals from the FERC, MPSC, NPSC and SDPUC, clearance under the HSR Act, consent of the FCC, and approval from each company's shareholders. The combined company will serve approximately 0.7 million electric utility customers and 1.5 million gas utility customers across eight states. See additional information in Item 1A - Risk Factors and Note 17 of the Notes to Consolidated Financial Statements in this Annual Report on Form 10-K.