黑山美股招股说明书(2025-09-26版)

$450,000,000 4.550% Notes due 2031 Black Hills Corporation is offering $450,000,000 aggregate principal amount of 4.550% Notes due2031 (the “Notes”). We will pay interest on the Notes on January 31 and July 31 of each year, beginning on January 31,2026. We may redeem some or all of the Notes at any time at the redemption prices described under thecaption “Description of the Notes — Optional Redemption.” The Notes have no sinking fund provisions. The Notes will be our senior unsecured obligations and will rank equally with all of our otherunsecured and unsubordinated indebtedness from time to time outstanding. The Notes will not be listed on any securities exchange, and there is no existing trading market for theNotes. Investing in the Notes involves risks. See “Risk Factors” beginning on pageS-5of this prospectussupplement. (1)Plus accrued interest from October2, 2025, if settlement occurs after that date. Delivery of the Notes in book-entry form only will be made through the facilities of The DepositoryTrust Company and its participants, including Clearstream Banking,société anonymeand EuroclearBankS.A./N.V., on or about October2, 2025, which is the fifth business day following the date of thisprospectus supplement (T+5). This settlement date may affect trading of the Notes. See “Underwriting.” Neither the Securities and Exchange Commission nor any other regulatory body has approved ordisapproved of these securities or determined if this prospectus supplement or the accompanying prospectus istruthful or complete. Any representation to the contrary is a criminal offense. Joint Book-Running Managers J.P. Morgan BofA Securities The date of this prospectus supplement is September25, 2025. Neither we nor the underwriters have authorized anyone to provide you with any information other thanthe information contained in or incorporated by reference in this prospectus supplement, the accompanyingprospectus and any free writing prospectus prepared by or on behalf of us or to which we have referred you. Weand the underwriters take no responsibility for, and can provide no assurance as to the reliability of, any otherinformation that others may give you. Neither we nor the underwriters are making an offer of these securities inany state or jurisdiction where the offer is not permitted. You should not assume that the information containedin or incorporated by reference in this prospectus supplement, the accompanying prospectus or any freewritingprospectus is accurate as of any date other than the date on the front of this prospectus supplement, the date ofthe accompanying prospectus or the date of such free writing prospectus, as applicable. TABLE OF CONTENTS Prospectus Supplement ABOUT THIS PROSPECTUS SUPPLEMENTS-iiFORWARD-LOOKING INFORMATIONS-iiPROSPECTUS SUPPLEMENT SUMMARYS-1RISK FACTORSS-5USE OF PROCEEDSS-7CAPITALIZATIONS-8DESCRIPTION OF THE NOTESS-9MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCESS-20BENEFIT PLAN INVESTOR CONSIDERATIONSS-25UNDERWRITINGS-27EXPERTSS-32LEGAL MATTERSS-32WHERE YOU CAN FIND MORE INFORMATIONS-33 ABOUT THIS PROSPECTUS1DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS1BLACK HILLS CORPORATION2RISK FACTORS3USE OF PROCEEDS4DESCRIPTION OF SENIOR DEBT SECURITIES5DESCRIPTION OF SUBORDINATED DEBT SECURITIES11DESCRIPTION OF CAPITAL STOCK18DESCRIPTION OF WARRANTS22DESCRIPTION OF PURCHASE CONTRACTS24DESCRIPTION OF UNITS25PLAN OF DISTRIBUTION26LEGAL OPINIONS28EXPERTS28WHERE YOU CAN FIND MORE INFORMATION29 ABOUT THIS PROSPECTUS SUPPLEMENT This prospectus supplement and the accompanying prospectus are part of a registration statement thatwe filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process.This document contains two parts. The first part consists of this prospectus supplement, which provides youwith specific information about the Notes that we are selling in this offering and about the offering itself.The second part is the accompanying prospectus, which provides more general information. If thedescription of this offering varies between this prospectus supplement and the accompanying prospectus,you should rely on the information contained in this prospectus supplement. Both this prospectus supplement and the accompanying prospectus include or incorporate by referenceimportant information about us, our securities and other information you should know before investing inour Notes. Before purchasing any Notes, you should carefully read both this prospectus supplement and theaccompanying prospectus, together with the additional information described under the heading “WhereYou Can Find More Information.” The terms “we”, “our”, “us”, the “Company” and “BHC” refer to Black Hills Corporation and itssubsidiaries unless the context suggests otherwise. The term “you” refers to a prospective investor. FORWARD-LOOKING INFORMATION Certain matters contained in or incorporated by reference in this prospectus supplement and theaccompanying prospectus