MDU RESOURCES GROUP INC — Earnings Release 2026

May 7, 2026

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): May 7, 2026

MDU Resources Group, Inc.

(Exact name of registrant as specified in its charter)

Delaware	1-03480	30-1133956
(State or other jurisdiction of	(Commission File Number)	(IRS Employer
incorporation)		Identification No.)

1200 West Century Avenue

P.O. Box 5650

Bismarck , North Dakota

(Address of principal executive offices)

58506
(Zip Code)

Registrant’s telephone number, including area code: ( 701 ) 530-1000

N/A
(Former name or former address, if changed since last report.)

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 2.02. Results of Operations and Financial Condition.

On May 7, 2026, MDU Resources Group, Inc. (the “Company”) issued a news release (the “News Release”) announcing its financial results for the first quarter of 2026. A copy of the News Release is furnished as Exhibit 99 to this Current Report on Form 8-K, which, in its entirety, is incorporated herein by reference.

The Company is webcasting a conference call on May 7, 2026, to discuss its first quarter 2026 financial results, during which the Company will provide an update on the business.

The information contained in Item 2.02 of this Current Report on Form 8-K, including Exhibit 99, shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, and shall not be deemed incorporated by reference into any filing under the Securities Act of 1933, as amended (the “Securities Act”), or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 7.01. Regulation FD Disclosure.

In conjunction with the News Release, the Company also made available an investor presentation concerning its first quarter 2026 financial results, which is available under the “Investor Relations” section of the Company’s corporate website, located at investor.mdu.com. Information on the Company’s corporate website is not, and will not be deemed to be, a part of this Current Report on Form 8-K or incorporated into any other filings the Company may make with the U.S. Securities and Exchange Commission.

The information contained in Item 7.01 of this Current Report on Form 8-K shall not be deemed “filed” for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities of that section, and shall not be deemed incorporated by reference into any filing under the Securities Act, or the Exchange Act, except as expressly set forth by specific reference in such filing.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.	Description
99	News Release, dated May 7, 2026.
104	Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURE

Pursuant to the requirements of the Exchange Act, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

MDU Resources Group, Inc.

Date: May 7, 2026
Jason L. Vollmer
Chief Financial Officer