Agreement Terminated

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): August 10, 2023 MDU Resources Group Inc (Exact name of registrant as specified in its charter) (State or other jurisdiction of (Commission File Number) (I.R.S. Employer Identification No.) incorporation) Delaware 1-03480 30-1133956 1200 West Century Avenue P.O. Box 5650 Bismarck , North Dakota 58506-5650 (Address of principal executive offices) (Zip Code) Registrant’s telephone number, including area code ( 701 ) 530-1000 Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))   Securities registered pursuant to Section 12(b) of the Securities Exchange Act of 1934: (Title of each class) (Trading Symbol(s)) (Name of each exchange on which registered) Common Stock, par value $1.00 per share MDU New York Stock Exchange Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 or Rule 12b-2 of the Securities Exchange Act of 1934. Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ Item 1.02. Termination of a Material Definitive Agreement. On August 10, 2023, MDU Resources Group, Inc. (the “Company”) provided notice of termination, effective August 10, 2023, of the Distribution Agreement, dated as of February 22, 2019, as amended on August 14, 2020 (the “Distribution Agreement”), that the Company had entered into with J.P. Morgan Securities LLC and MUFG Securities Americas Inc., as agents (together, the “Agents”). As previously reported, pursuant to the terms of the Distribution Agreement, the Company could issue and sell from time to time, in the manner and subject to the terms and conditions described in the Distribution Agreement, up to 6,398,889 shares of the Company’s common stock, $1.00 par value per share (the “Common Stock”), to or through the Agents. Prior to the termination, the Company had capacity to issue approximately 3.6 million additional shares of Common Stock pursuant to the Distribution Agreement. The Company is not subject to any termination penalties related to the termination of the Distribution Agreement. Item 9.01. Financial Statements and Exhibits. (d)    Exhibits. Exhibit Number Description 104 Cover Page Interactive Data File (embedded within the Inline XBRL document). 2 SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Date: August 10, 2023 MDU Resources Group, Inc. By: /s/ Paul R. Sanderson Paul R. Sanderson Vice President, Chief Legal Officer     and Secretary 3