MDU / MDU Resources Group, Inc. - Pemfailan SEC, Laporan Tahunan, Penyata Proksi

MDU Resources Announces Appointments to the Board of Directors

Exhibit 99.1 MDU Resources Announces Appointments to the Board of Directors Bismarck, ND – August 13, 2025 – MDU Resources Group, Inc. (NYSE: MDU) today announced the election of Charles M. Kelley and Tammy J. Miller to its board of directors, effective Aug. 12, 2025. Kelley brings more than four decades of experience in the natural gas industry, including a distinguished 25-year career at ONEOK,

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 12, 2025 MDU Resources Gro

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 12, 2025 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) (

Up to $400,000,000

Filed Pursuant to Rule 424(b)(5) Registration No. 333-289348   PROSPECTUS SUPPLEMENT (To Prospectus Dated August 7, 2025) Up to $400,000,000   MDU Resources Group, Inc. Common Stock We may issue, offer and sell up to an aggregate of $400,000,000 of our common stock, $1.00 par value per share (“common stock”) from time to time through Wells Fargo Securities, LLC (“Wells Fargo”) and BofA Securities,

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 ☐ TRANSITION REPORT PURSUANT TO S

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP, INC

Calculation of Filing Fee Tables 424(b)(5) (Form Type)S-3 MDU RESOURCES GROUP, INC. (Exact Name of Registrant as Specified in its Charter) 333-289348Table 1: Newly Registered and Carry Forward Securities N/A

EXHIBIT 107 Calculation of Filing Fee Tables 424(b)(5) (Form Type)S-3 MDU RESOURCES GROUP, INC.

MDU Resources Announces Second Quarter 2025 Results; Updates Guidance

MDU Resources Announces Second Quarter 2025 Results; Updates Guidance •Solid performance in the pipeline segment driven by higher transportation revenue •Electric utility and natural gas distribution customer base achieves combined targeted growth rate at 1.

Consent of Deloitte & Touche LLP.

Exhibit 23(a) CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in this Registration Statement on Form S-3 of our reports dated February 20, 2025, relating to the financial statements of MDU Resources Group, Inc.

Consent of Perkins Coie LLP (included in Exhibit 5(a)).

 Exhibit 5(a) Perkins Coie LLP 1900 Sixteenth Street Suite 1400 Denver, CO 80202-5255 T.

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 7, 2025 MDU Resources Grou

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 7, 2025 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) (I

Form of Master Forward Sale Confirmation.

Exhibit 1.2 To: MDU Resources Group, Inc. From: [Dealer] Re: Issuer Share Forward Sale Transactions Date: [ ], 2025 Ladies and Gentlemen: The purpose of this communication (this “Master Confirmation”) is to set forth the terms and conditions of the transactions to be entered into from time to time between [ ] (“Dealer”), through its agent [ ] (the “Agent”), and MDU Resources Group, Inc. (“Counterp

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Nicole A. Kivisto, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to t

As filed with the Securities and Exchange Commission on August 7, 2025

As filed with the Securities and Exchange Commission on August 7, 2025 Registration Statement No.

Filing Fee Table.

EXHIBIT 107 Calculation of Filing Fee Tables Form S-3ASR (Form Type) MDU RESOURCES GROUP, INC.

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 7, 2025 MDU Resources Grou

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 7, 2025 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) (I

Distribution Agreement, dated August 7, 2025.

Exhibit 1.1 Execution Version DISTRIBUTION AGREEMENT August 7, 2025 Wells Fargo Securities, LLC 500 West 33rd Street, 14th Floor New York, New York 10001   BofA Securities, Inc. One Bryant Park New York, New York 10036 In their separate capacities as Agents and Forward Sellers     Wells Fargo Bank, National Association 500 West 33 Street, 14th Floor New York, New York 10001   Bank of America, N.A.

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K/A (Amendment No. 1) ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 o TRANSITION REPORT PUR

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K/A (Amendment No. 1) ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR o TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP,

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 o TRANSITION REPORT PURSUANT TO SECTION 15(

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR o TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP, INC. 401(k) RETIREM

Conflict Minerals Report as described in Items 1.01 and 1.02 of this Form SD

Exhibit 1.01 MDU Resources Group, Inc. Conflict Minerals Report For the Year Ended December 31, 2024 Introduction On October 31, 2024, MDU Resources Group, Inc. (the “Company”) completed the separation of Everus Construction Group, Inc., the Company’s former construction services business (“Everus”), from the Company, resulting in Everus becoming an independent, publicly-traded company (the “Separ

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM SD SPECIALIZED DISCLOSURE REPORT MDU Resources Group, Inc. (Exact name of registrant as specified in its charter)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM SD SPECIALIZED DISCLOSURE REPORT 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 Identification No.) incorporation) 1200 West Century Avenue P.O. Box 5650 Bismarck, North Dakota 58506 Anthony

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Amendment to Registrant's Code of Ethics, or Waiver of a Provision of the Code of Ethics, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

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 13, 2025 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

MDU Resources Group, Inc. Long-Term Performance

MDU Resources Group, Inc. Long-Term Performance-Based Incentive Plan (Amended and Restated as of May 14, 2025) Article 1. Establishment, Purpose, and Duration 1.1 Establishment of the Plan. MDU Resources Group, Inc., a Delaware corporation (the "Company"), hereby amends and restates this long-term incentive compensation plan, known as the "MDU Resources Group, Inc. Long-Term Performance-Based Ince

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Nicole A. Kivisto, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to t

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 8, 2025 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

MDU Resources Delivers Strong Start to 2025; Affirms Guidance

MDU Resources Delivers Strong Start to 2025; Affirms Guidance •Pipeline segment reports record first quarter earnings, up 13.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 ☐ TRANSITION REPORT PURSUANT TO

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP, IN

MDU RESOURCES GROUP, INC. and 2025 Proxy Statement 2024 ANNUAL REPORT DEAR STOCKHOLDERS: 2024 has been a transformational year for MDU Resources, as we embarked on a new era as a pure-play regulated energy delivery business. The successful tax-free s

MDU RESOURCES GROUP, INC. and 2025 Proxy Statement 2024 ANNUAL REPORT DEAR STOCKHOLDERS: 2024 has been a transformational year for MDU Resources, as we embarked on a new era as a pure-play regulated energy delivery business. The successful tax-free spinoff of Everus Construction Group, our former construction services business, has sharpened our strategic focus, optimizing value for our stockholde

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ý Filed by a party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ý Definitive

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ý Filed by a party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

nsider Trading Policy

1200 West Century Avenue, P.O. Box 5650 Bismarck, North Dakota 58506-5650 POLICY STATEMENTS Policy No. 87.2 Insider Trading Policy Effective Date: February 13, 2025 I.PURPOSE It is illegal for any director, officer, or employee of MDU Resources Group, Inc. and its subsidiaries (the “Company”), who possesses material non-public information concerning the Company to engage in transactions concerning

Form of Performance Share Award Agreement (TSR) under the Long-Term Performance-Based Incentive Plan, as amended

MDU RESOURCES GROUP, INC. LONG-TERM PERFORMANCE-BASED INCENTIVE PLAN PERFORMANCE SHARE ("PSA") AWARD AGREEMENT (Based on the Relative TSR Performance of MDU Resources Group, Inc.) [Date] [Participant Name] In accordance with the terms of the MDU Resources Group, Inc. (the "Company") Long-Term Performance-Based Incentive Plan (the "Plan"), pursuant to action of the Compensation and Human Capital Co

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 ☐ TRANSITION REPORT PURSUANT TO SECTI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP, INC. (E

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this annual report on Form 10-K of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the p

MDU Resources Group, Inc. Director Compensation Policy, as amended May 15, 2024

MDU RESOURCES GROUP, INC. DIRECTOR COMPENSATION POLICY Each director of MDU Resources Group, Inc. (the “Company”) who is not a full-time employee of the Company (a “Director”) shall receive compensation made up of annual cash retainers and shares of the Company’s common stock (“Common Stock”), as set forth in this policy. Director Compensation Annual Cash Retainers Base Retainer $110,000* Addition

Subsidiaries of MDU Resources Group, Inc.

MDU RESOURCES GROUP, INC. List of Subsidiaries (effective December 31, 2024) Subsidiaries Formation Jurisdiction Cascade Natural Gas Corporation Washington CEHI, LLC Delaware Centennial Holdings Capital LLC Delaware Fidelity Exploration & Production Company Delaware FutureSource Capital Corp. Delaware Intermountain Gas Company Idaho InterSource Insurance Company Vermont MDU BenefitCo II, Inc. Dela

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Nicole A. Kivisto, certify that: 1.I have reviewed this annual report on Form 10-K of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the

MDU Resources Group, Inc. Executive Incentive Compensation Plan, as amended February 13, 2025

MDU RESOURCES GROUP, INC. EXECUTIVE INCENTIVE COMPENSATION PLAN I. ESTABLISHMENT AND PURPOSE This Executive Incentive Compensation Plan (this “Plan”), as amended and restated as of February 13, 2025, and as may be subsequently amended from time to time, of MDU Resources Group, Inc. (the “Company”), is to provide an incentive for officers and key employees of the Company and its subsidiaries to foc

under the Long-Term Performance-Based Incentive Plan,

MDU RESOURCES GROUP, INC. LONG-TERM PERFORMANCE-BASED INCENTIVE PLAN PERFORMANCE SHARE ("PSA") AWARD AGREEMENT (Based on the Absolute Performance of MDU Resources Group, Inc.) [Date] [Participant Name] In accordance with the terms of the MDU Resources Group, Inc. (the "Company") Long-Term Performance-Based Incentive Plan (the "Plan"), pursuant to action of the Compensation and Human Capital Commit

Restricted Stock Unit Award Agreement under the Long-Term Performance-Based Incentive Plan, as amended

MDU RESOURCES GROUP, INC. LONG-TERM PERFORMANCE-BASED INCENTIVE PLAN RESTRICTED STOCK UNIT ("RSU") AWARD AGREEMENT [Date] [Participant Name] In accordance with the terms of the MDU Resources Group, Inc. (the "Company") Long-Term Performance-Based Incentive Plan (the "Plan"), pursuant to action of the Compensation and Human Capital Committee (the "Committee") of the Company's Board of Directors, th

Bylaws of MDU Resources Group, Inc.

EXHIBIT 3.1 169745278.8 BYLAWS OF (a Delaware corporation) Amended and Restated as of February 13, 2025 i 169745278.8 TABLE OF CONTENTS Page ARTICLE I OFFICES…………………………………………………… 1 ARTICLE II MEETINGS OF STOCKHOLDERS……………………….. 1 ARTICLE III DIRECTORS……………………………………………… 20 ARTICLE IV NOTICES………………………………………………… 22 ARTICLE V OFFICERS………………………………………………… 22 ARTICLE VI CERTIFICATES OF STOCK………………………………

Badger Wind Purchase and Sale Agreement between Badger Wind, LLC, and Montana-Dakota Utilities Co., dated February 13, 2025.

Execution Version US-DOCS\155424210.18 BADGER WIND PURCHASE AND SALE AGREEMENT between BADGER WIND, LLC as the Seller and MONTANA-DAKOTA UTILITIES CO. as the Buyer February 13, 2025 Exhibit 10.1* 1 US-DOCS\155424210.18 Badger Wind Purchase and Sale Agreement This Purchase and Sale Agreement (this “Agreement”) is entered into as of February 13, 2025 (the “Effective Date”), between Badger Wind, LLC,

Regulation FD Disclosure, Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Entry into a Material Definitive Agreement

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): February 14, 2025 (February 13, 2025) MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) Delaware 1-03480 30-1133956 (State or other jurisdiction of (Com

MDU Resources Announces Plans to Invest in Badger Wind Farm

Exhibit 99.1 MDU Resources Announces Plans to Invest in Badger Wind Farm Bismarck, ND – February 14, 2025 – MDU Resources Group, Inc. (NYSE: MDU) is pleased to announce that its subsidiary, Montana-Dakota Utilities Co. (MDU), has signed a purchase agreement to acquire a 49% ownership interest in the Badger Wind Farm. This acquisition represents 122.5 MW of the project's total 250 MW generation cap

MDU Resources Reports Strong Performance; Initiates Guidance for 2025

MDU Resources Reports Strong Performance; Initiates Guidance for 2025 •Net income of $281.

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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): February 6, 2025 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)

Regulation FD Disclosure, Financial Statements and Exhibits

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): November 21, 2024 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)

MDU Resources Group Announces Increased Capital Investment Plan for 2025-2029

MDU Resources Group Announces Increased Capital Investment Plan for 2025-2029 BISMARCK, ND – Nov.

MDU Resources Welcomes Vernon Dosch to Board of Directors

Exhibit 99.1 MDU Resources Welcomes Vernon Dosch to Board of Directors BISMARCK, N.D. — Nov. 14, 2024 — MDU Resources Group, Inc. (NYSE: MDU) today announced that its board of directors has elected Vernon A. Dosch as a director, effective Nov. 15, 2024. Dosch, a respected leader with more than 45 years of expertise in the electric utility and broadband industries, brings a deep commitment to commu

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): November 14, 2024 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)

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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) November 7, 2024 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 Identificat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 ☐ TRANSITION REPORT PURSUANT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP

MDU Resources Reports Strong Q3 Earnings, Increases 2024 Guidance

MDU Resources Reports Strong Q3 Earnings, Increases 2024 Guidance Key Financial Highlights for Third Quarter 2024: •Electric earnings of $24.

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Nicole A. Kivisto, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to t

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

MDU Resources Group, Inc. UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS

MDU Resources Group, Inc. UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS On October 31, 2024, MDU Resources Group, Inc. (“MDU Resources”, the “Company”, “we”, “our”, and “us”) entered into a Separation and Distribution Agreement (the “Separation and Distribution Agreement”) with Everus Construction Group, Inc. (“Everus”). The Separation was structured as a generally tax-free spin-off, where

Financial Statements and Exhibits

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): October 31, 2024 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 Identifica

MDU Resources Group, Inc. and Everus Construction Group, Inc.

Exhibit 10.3 EMPLOYEE MATTERS AGREEMENT BY AND BETWEEN MDU RESOURCES GROUP, INC. AND EVERUS CONSTRUCTION GROUP, INC. DATED AS OF OCTOBER 31, 2024 TABLE OF CONTENTS Page Article I. DEFINITIONS Section 1.01 Definitions 1 Section 1.02 Interpretation 6 Article II. GENERAL PRINCIPLES FOR ALLOCATION OF LIABILITIES Section 2.01 General Principles 6 Section 2.02 Service Credit Recognized by SpinCo and Spi

aration and Distribution Agreement, dated as of October 3

Exhibit 2.1 SEPARATION AND DISTRIBUTION AGREEMENT BY AND BETWEEN MDU RESOURCES GROUP, INC. AND EVERUS CONSTRUCTION GROUP, INC. DATED AS OF OCTOBER 31, 2024 TABLE OF CONTENTS Page ARTICLE I DEFINITIONS 5 1.1 Definitions 5 ARTICLE II THE SEPARATION 16 2.1 Transfer of Assets and Assumption of Liabilities 16 2.2 SpinCo Assets; Parent Assets 19 2.3 SpinCo Liabilities; Parent Liabilities 21 2.4 Approval

MDU Resources Group, Inc. and Everus Construction Group, Inc.

Exhibit 10.2 TAX MATTERS AGREEMENT DATED AS OF OCTOBER 31, 2024 BY AND BETWEEN MDU RESOURCES GROUP, INC. AND EVERUS CONSTRUCTION GROUP, INC. TABLE OF CONTENTS Page Section 1. Definition of Terms 2 Section 2. Allocation of Tax Liabilities 12 Section 2.01 General Rule 12 Section 2.02 Allocation of United States Federal Income Tax and Federal Other Tax 12 Section 2.03 Allocation of State Income Tax a

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Entry into a Material Definitive Agreement, Termination of a Material Definitive Agreement, Financial Statements and Exhibits, Completion of Acquisition or Disposition of Assets

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): October 31, 2024 MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation) (Commission File Number) (I.R.S. Empl

MDU Resources Group, Inc. and Everus Construction Group, Inc.

Exhibit 10.1 TRANSITION SERVICES AGREEMENT BY AND BETWEEN MDU RESOURCES GROUP, INC. AND EVERUS CONSTRUCTION GROUP, INC. DATED AS OF OCTOBER 31, 2024 TABLE OF CONTENTS Page ARTICLE I DEFINITIONS 2 Section 1.1. Definitions 2 ARTICLE II SERVICES 4 Section 2.1. Services 4 Section 2.2. Performance of Services 5 Section 2.3. Charges for Services 6 Section 2.4. Reimbursement for Out-of-Pocket Costs and E

MDU Resources Completes Spinoff of Everus Construction Group

Exhibit 99.1 MDU Resources Completes Spinoff of Everus Construction Group BISMARCK, N.D., Nov. 1, 2024 – MDU Resources Group, Inc. (NYSE: MDU) today announced the successful completion of the spinoff of its construction services subsidiary, Everus Construction Group (NYSE: ECG). As a result of the spin-off, Everus is now an independent public company. “This achievement is truly remarkable, and a t

MDU / MDU Resources Group, Inc. / Corvex Management LP Activist Investment

SC 13D/A 1 formsc13da-mdu.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 6)* MDU RESOURCES GROUP, INC. (Name of Issuer) Common Stock, par value $1.00 per share (Title of Class of Securities) 552690109 (CUSIP Number) Keith Meister Patrick J. Dooley, Esq. Corvex Management LP 667 Madison Avenue New Yor

Everus Construction Group Holding Investor and Analyst Information Event Today at NYSE

Exhibit 99.2 Everus Construction Group Holding Investor and Analyst Information Event Today at NYSE Bismarck, N.D. — Oct. 17, 2024 — Everus Construction Group, an industry-leading construction services provider, will hold an analyst and investor day at 10 a.m. EDT today at the New York Stock Exchange. At the event, management will provide an overview of the company’s 4EVER strategic framework, inv

Regulation FD Disclosure, Financial Statements and Exhibits

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): October 17, 2024 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 Identifica

www.EVERUS.com 1 INVESTOR DAY October 17, 2024 Exhibit 99.1 ©2024 EVERUS Forward-Looking Statements 2 This presentation and other materials Everus has filed or will file with the Securities and Exchange Commission ("SEC") (and oral communications tha

www.EVERUS.com 1 INVESTOR DAY October 17, 2024 Exhibit 99.1 ©2024 EVERUS Forward-Looking Statements 2 This presentation and other materials Everus has filed or will file with the Securities and Exchange Commission ("SEC") (and oral communications that Everus may make) contain or incorporate by reference, or will contain or incorporate by reference, certain “forward-looking statements” within the m

MDU Resources Board of Directors Approves Everus Spinoff, Declares Distribution of Shares of Everus

Exhibit 99.1 MDU Resources Board of Directors Approves Everus Spinoff, Declares Distribution of Shares of Everus BISMARCK, N.D. — Oct. 2, 2024 — MDU Resources Group, Inc. (NYSE: MDU) announced today that its board of directors has approved the previously announced spinoff of the company’s wholly owned construction services subsidiary, Everus Construction Group, through a pro rata distribution of a

Financial Statements and Exhibits, Other Events

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): October 1, 2024 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 Identificatio

MDU Resources Announces Anticipated Board of Directors for Everus

Exhibit 99.1 MDU Resources Announces Anticipated Board of Directors for Everus BISMARCK, N.D. — Sept. 3, 2024 — MDU Resources Group, Inc. (NYSE: MDU) today announced the anticipated board of directors for Everus Construction Group, effective upon completion of the planned spinoff of the construction services subsidiary into an independent, publicly traded company. The spinoff is expected to be com

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): September 3, 2024 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 Identificat

MDU Resources Appoints Two to Board of Directors

Exhibit 99.1 MDU Resources Appoints Two to Board of Directors BISMARCK, N.D. — Aug. 15, 2024 — MDU Resources Group, Inc. (NYSE: MDU) announced today that Michael S. Della Rocca and Marian M. Durkin have been appointed to the company’s board of directors. Della Rocca, during his 35-year career, held a number of executive positions within the engineering and construction industry, including as chief

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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 15, 2024 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 Identificatio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 ☐ TRANSITION REPORT PURSUANT TO S

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP INC

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

Montana-Dakota Utilities Co. Note Purchase Agreement, dated July 11, 2024

EX-4.A 5 a2024q2ex4a.htm MDU NOTE PURCHASE AGREEMENT EXECUTION COPY Montana-Dakota Utilities Co. $72,000,000 5.90% Senior Notes due July 11, 2039 $53,000,000 6.03% Senior Notes due July 11, 2054 Note Purchase Agreement Dated July 11, 2024 {00529100.DOC; 9} TABLE OF CONTENTS SECTION HEADING PAGE SECTION 1. AUTHORIZATION OF NOTES 1 SECTION 2. SALE AND PURCHASE OF NOTES 1 SECTION 3. CLOSING 2 SECTION

MDU Resources Reports Solid Q2 Earnings, Updates 2024 Guidance

MDU Resources Reports Solid Q2 Earnings, Updates 2024 Guidance Key Financial Highlights for Second Quarter 2024: •Pipeline achieved record second quarter earnings of $17.

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 8, 2024 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

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Nicole A. Kivisto, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to t

MDU Resources’ Board of Directors Names Leadership for Everus Construction Group, Effective on Spinoff

Exhibit 99.1 MDU Resources’ Board of Directors Names Leadership for Everus Construction Group, Effective on Spinoff BISMARCK, N.D. — July 18, 2024 — MDU Resources Group, Inc.’s (NYSE: MDU) board of directors has selected the management team to lead Everus Construction Group, the company’s construction services subsidiary, effective when the anticipated spinoff of Everus into an independent, public

Financial Statements and Exhibits, Other Events

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): July 18, 2024 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

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 o TRANSITION REPORT PURSUANT TO SECTION 15(

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 OR o TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP, INC. 401(k) RETIREM

Exhibit 1.01 - Conflict Minerals Report as required by Items 1.01 and 1.02 of this Form SD.

Exhibit 1.01 MDU Resources Group, Inc. Conflict Minerals Report For The Year Ended December 31, 2023 Introduction This Conflict Minerals Report (the “Report”) has been prepared pursuant to Rule 13p-1 under the Securities Exchange Act of 1934 (the “Rule”), for the reporting period from January 1 to December 31, 2023. The Report relates to the process undertaken by MDU Resources Group, Inc. (herein

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM SD SPECIALIZED DISCLOSURE REPORT MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) Delaware 1-03480 30-1133956 (State or other jurisdiction of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM SD SPECIALIZED DISCLOSURE REPORT MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) Delaware 1-03480 30-1133956 (State or other jurisdiction of Incorporation) (Commission File Number) (I.R.S. Employer Identification No.) 1200 West Century Avenue P.O. Box 5650 Bismarck, North Dakota 58506-5650

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 14, 2024 MDU Resources Group

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 14, 2024 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 N

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Nicole A. Kivisto, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to t

inth Amendment to MDU Resources Group, Inc. 401

NINTH AMENDMENT TO MDU RESOURCES GROUP, INC. 401(k) RETIREMENT PLAN The MDU Resources Group, Inc. 401(k) Retirement Plan (the "Plan"), as most recently amended and restated effective April 1, 2020, is hereby amended by this Ninth Amendment effective as of the dates or periods specified below. All terms defined in the Plan shall have the same meanings when used herein. 1.Effective January 1, 2022,

MDU Resources Reports Strong First Quarter Results; Affirms 2024 Guidance

MDU Resources Reports Strong First Quarter Results; Affirms 2024 Guidance •Pipeline has record first quarter earnings, up 82%.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 ☐ TRANSITION REPORT PURSUANT TO

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP INC

nc. Term Loan Agreement, dated April 1, 2024, amo

Execution Version TERM LOAN AGREEMENT dated as of April 1, 2024 among WBI ENERGY TRANSMISSION, INC.

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 2, 2024 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.

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

Amendment to MDU Resources Group, Inc. 401(k) Retirement Plan. as amended

TENTH AMENDMENT TO MDU RESOURCES GROUP, INC. 401(k) RETIREMENT PLAN The MDU Resources Group, Inc. 401(k) Retirement Plan (the "Plan"), as most recently amended and restated effective April 1, 2020, is hereby amended by this Tenth Amendment effective April 1, 2024. All terms defined in the Plan shall have the same meanings when used herein. 1. Section 4.6(b) shall be amended by striking "$5,000" in

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ý Filed by a party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ý Filed by a party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

DEFA14A 1 a2024proxynotice.htm DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ý Filed by a party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commiss

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): March 14, 2024 MDU Resources Gro

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): March 14, 2024 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

, 2024, by and among Keith A. Meister, Corvex Management LP and MDU Resources Group, Inc.

Exhibit 10.1 This AMENDED & RESTATED COOPERATION AGREEMENT (this “Agreement”), dated as of March 14, 2024, is by and among Keith A. Meister, Corvex Management LP (Mr. Meister and Corvex Management LP, together with their respective affiliates, the “Corvex Group”) and MDU Resources Group, Inc. (the “Company”), and amends and restates, in its entirety, the original Cooperation Agreement, dated as of

MDU / MDU Resources Group, Inc. / Corvex Management LP Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 5)* MDU RESOURCES GROUP, INC. (Name of Issuer) Common Stock, par value $1.00 per share (Title of Class of Securities) 552690109 (CUSIP Number) Keith Meister Patrick J. Dooley, Esq. Corvex Management LP 667 Madison Avenue New York, NY 10065 (212) 474-6700 COP

Regulation FD Disclosure, Financial Statements and Exhibits

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): March 13, 2024 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

MDU Resources Affirms 2024 Guidance, Updates Long-Term Earnings Per Share Guidance

Exhibit 99.1 MDU Resources Affirms 2024 Guidance, Updates Long-Term Earnings Per Share Guidance BISMARCK, N.D. — March 13, 2024 — MDU Resources Group, Inc. (NYSE: MDU) announced that it is affirming 2024 financial guidance and providing an updated long-term earnings per share growth rate outlook in advance of planned investor meetings today. MDU Resources affirmed its 2024 guidance information, wh

Consent of Perkins Coie LLP (included in Exhibit 5(a)).

Exhibit 5(a) February 23, 2024 MDU Resources Group, Inc. 1200 West Century Avenue P.O. Box 5650 Bismarck, North Dakota 58506-5650 Re: Registration Statement on Form S-8 of Shares of Common Stock, $1.00 par value per share, of MDU Resources Group, Inc. Ladies and Gentlemen: We have acted as counsel to MDU Resources Group, Inc., a Delaware corporation (the “Company”), in connection with the preparat

Consent of Baker Tilly US, LLP.

Exhibit 23(b) CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in the Registration Statement on Form S-8 of MDU Resources Group, Inc.

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) MDU Resources Group, Inc.

As filed with the Securities and Exchange Commission on February 23, 2024

As filed with the Securities and Exchange Commission on February 23, 2024 Registration No.

Consent of Deloitte & Touche LLP.

Exhibit 23(a) CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM We consent to the incorporation by reference in this Registration Statement on Form S-8 of our reports dated February 22, 2024, relating to the financial statements and financial statement schedules of MDU Resources Group, Inc.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 ☐ TRANSITION REPORT PURSUANT TO SECTI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP INC (Exa

Amendment to MDU Resources Group, Inc. 401(k) Retirement Plan, as amended

SEVENTH AMENDMENT TO MDU RESOURCES GROUP, INC. 401(k) RETIREMENT PLAN The MDU Resources Group, Inc. 401(k) Retirement Plan (the “Plan”), as most recently amended and restated effective April 1, 2020, is hereby amended by this Seventh Amendment effective as of the date this Amendment is signed. All terms defined in the Plan shall have the same meanings when used herein. 1. Section 3.1(e) shall be a

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Nicole A. Kivisto, certify that: 1.I have reviewed this annual report on Form 10-K of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the

Incentive Compensation Recovery Policy

POLICY STATEMENTS Policy No. 89.0 Incentive Compensation Recovery Policy Effective Date: October 2, 2023 I.PURPOSE MDU Resources Group, Inc. Incentive Compensation Recovery Policy (this “Policy”) is to provide for the recovery of certain Incentive-Based Compensation in the event of an Accounting Restatement. This Policy is intended to comply with, and to be administered and interpreted consistent

Amendment to MDU Resources Group, Inc. 401(k) Retirement Plan, as amended

EIGHTH AMENDMENT TO MDU RESOURCES GROUP, INC. 401(k) RETIREMENT PLAN The MDU Resources Group, Inc. 401(k) Retirement Plan (the “Plan”), as most recently amended and restated effective April 1, 2020, is hereby amended by this Eighth Amendment effective as of January 1, 2024. All terms defined in the Plan shall have the same meanings when used herein. 1.The definition of “Eligible Employee” in Artic

MDU Resources Group, Inc. Section 16 Officers and Directors with Indemnification Agreements Chart, as of February 14, 2024

MDU Resources Group, Inc. Section 16 Officers and Directors with Indemnification Agreements Chart As of February 14, 2024 Section 16 Officers Name Title Date of Agreement Nicole A. Kivisto President and Chief Executive Officer, MDU Resources Group, Inc. August 12, 2010, as amended May 15, 2014 Rob L Johnson President, WBI Energy, Inc. May 10, 2023 Anne M. Jones Vice President and Chief Human Resou

Amendment to MDU Resources Group, Inc. 401(k) Retirement Plan, as amended

SIXTH AMENDMENT TO MDU RESOURCES GROUP, INC. 401(k) RETIREMENT PLAN The MDU Resources Group, Inc. 401(k) Retirement Plan (the “Plan”), as most recently amended and restated effective April 1, 2020, is hereby amended by this Sixth Amendment effective as of May 1, 2023. All terms defined in the Plan shall have the same meanings when used herein. 1.The Introduction of the Plan shall be amended by add

Subsidiaries of MDU Resources Group, Inc.

MDU RESOURCES GROUP, INC. List of Subsidiaries (effective December 31, 2023) Subsidiaries Formation Jurisdiction Bombard Electric, LLC Nevada Bombard Mechanical, LLC Nevada Capital Electric Construction Company, Inc. Kansas Capital Electric Line Builders, LLC Kansas Cascade Natural Gas Corporation Washington CEHI, LLC Delaware Centennial Holdings Capital LLC Delaware Desert Fire Holdings, Inc. Nev

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this annual report on Form 10-K of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the p

MDU Resources Group, Inc. Change in Control Severance Plan

Exhibit 10.1 MDU RESOURCES GROUP, INC. CHANGE IN CONTROL SEVERANCE PLAN SECTION 1 PURPOSE OF THE PLAN The Board of Directors (the “Board”) of MDU Resources Group, Inc. recognizes that the possibility of a Change in Control (as defined in Section 2.4) of the Company (as defined below), and the uncertainty it could create, may result in the loss or distraction of employees of the Company to the detr

MDU Resources Group, Inc. Long-Term Performance-Based Incentive Plan, as amended February 15, 2024

Exhibit 10.2 MDU RESOURCES GROUP, INC. LONG-TERM PERFORMANCE-BASED INCENTIVE PLAN Article 1. Establishment, Purpose and Duration 1.1 Establishment of the Plan. MDU Resources Group, Inc., a Delaware corporation (hereinafter referred to as the "Company"), hereby establishes an incentive compensation plan to be known as the "MDU Resources Group, Inc. Long-Term Performance-Based Incentive Plan" (herei

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): February 15, 2024 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 Identificat

MDU / MDU Resources Group, Inc. / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SC 13G/A 1 tv0089-mduresourcesgroupinc.htm SCHEDULE 13G/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 12)* Name of issuer: MDU Resources Group Inc Title of Class of Securities: Common Stock CUSIP Number: 552690109 Date of Event Which Requires Filing of this Statement: December 29, 2023 Check the appropriate box to

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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) February 8, 2024 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 Identificatio

MDU Resources Reports Robust Growth in 2023; Initiates Guidance for 2024

MDU Resources Reports Robust Growth in 2023; Initiates Guidance for 2024 •Record electric retail sales volumes.

MDU Resources Announces Five-Year Capital Investment Plan

MDU Resources Announces Five-Year Capital Investment Plan BISMARCK, N.D. — Nov. 21, 2023 — MDU Resources Group, Inc. (NYSE: MDU) announced today that it plans to make capital investments totaling $2.8 billion from 2024 through 2028. “Our capital investment plans over the next five years are heavily focused on our regulated energy delivery businesses, with a 15% increase in planned spending as comp

Regulation FD Disclosure, Financial Statements and Exhibits

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) November 21, 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 Identificati

MDU Resources Appoints Darrel T. Anderson to Board of Directors

Exhibit 99.1 MDU Resources Appoints Darrel T. Anderson to Board of Directors BISMARCK, N.D. — Nov. 17, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today announced that Darrel T. Anderson has been appointed to the company’s board of directors. Anderson previously was the president and CEO of IDACORP and Idaho Power Company, an integrated electric utility serving customers in Idaho and Oregon. Ande

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): November 16, 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 Identificat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 ☐ TRANSITION REPORT PURSUANT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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) November 2, 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 Identificatio

Regulation FD Disclosure, Financial Statements and Exhibits

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): November 1, 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 Identificati

MDU Resources Reports Third Quarter Earnings, Increases Guidance

MDU Resources Reports Third Quarter Earnings, Increases Guidance BISMARCK, N.D. — Nov. 2, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today reported third quarter earnings on a generally accepted accounting principles (GAAP) basis of $74.9 million, or 37 cents per share, compared to third quarter 2022 GAAP earnings of $147.9 million, or 73 cents per share. Third quarter 2023 income from continuin

MDU Resources Plans to Spin Off Construction Services Business

Exhibit 99.1 MDU Resources Plans to Spin Off Construction Services Business BISMARCK, N.D. — Nov. 2, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today announced that its board of directors has approved a plan to spin off the company’s wholly owned construction services business, MDU Construction Services Group, Inc., to the shareholders of MDU Resources, resulting in two independent, publicly tra

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, David L. Goodin, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the

MDU Resources President and CEO Goodin to Retire; Kivisto Named Successor

Exhibit 99.1 MDU Resources President and CEO Goodin to Retire; Kivisto Named Successor BISMARCK, N.D. — Aug. 17, 2023 — David L. Goodin, president and CEO of MDU Resources Group, Inc. (NYSE: MDU), announced today that he intends to retire on Jan. 5, after a 40-year career with the company. The board of directors unanimously selected Nicole A. Kivisto, currently president and CEO of MDU Resources’

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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 17, 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 Identificatio

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 Gr

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 Identificatio

MDU Resources Declares Quarterly Dividend on Common Stock, Establishes Future Dividend Target

Exhibit 99.1 MDU Resources Declares Quarterly Dividend on Common Stock, Establishes Future Dividend Target BISMARCK, N.D. — Aug. 3, 2023 —MDU Resources Group, Inc.’s (NYSE: MDU) board of directors has declared a quarterly dividend on the company’s common stock of 12.5 cents per share. On an annualized basis, this dividend is approximately a 66% payout ratio based on the midpoint of MDU Resources’

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 3, 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

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 ☐ TRANSITION REPORT PURSUANT TO S

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP INC

Mine Safety Disclosures

MDU RESOURCES GROUP, INC. MINE SAFETY INFORMATION The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) requires issuers to include in periodic reports filed with the SEC certain information relating to citations or orders for violations of standards under the Federal Mine Safety and Health Act of 1977 (Mine Act), as amended by the Mine Improvement and New Emergency Respon

MDU Resources Reports Higher Second Quarter Earnings, Increases Guidance

MDU Resources Reports Higher Second Quarter Earnings, Increases Guidance BISMARCK, N.

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, David L. Goodin, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the

Financial Statements and Exhibits, Other Events

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 2, 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

MDU Resources to Pursue Tax-Advantaged Separation of Construction Services Business

Exhibit 99.1 MDU Resources to Pursue Tax-Advantaged Separation of Construction Services Business BISMARCK, N.D. — July 10, 2023 — Upon completing MDU Resources Group, Inc.’s (NYSE: MDU) previously announced strategic review of its wholly owned construction services business, MDU Construction Services Group Inc., the MDU Resources board of directors has determined that it will pursue a potential ta

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): July 10, 2023 MDU Resources Grou

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): July 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

The MDU Resources Group, Inc. 401(k) Retirement Plan’s Annual Report on Form 11-K for the year ended December 31, 2022, filed with the Commission on June 21, 2023.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR o TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP, INC. 401(k) RETIREM

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A (Amendment No. 1) 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 30, 2023

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K/A (Amendment No. 1) 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 30, 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. Employ

MDU Resources Group, Inc. UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS

MDU Resources Group, Inc. UNAUDITED PRO FORMA CONSOLIDATED FINANCIAL STATEMENTS On May 30, 2023, MDU Resources Group, Inc. (“MDU Resources”, the “Company”, “we”, “our” and “us”) entered into a Separation and Distribution Agreement (the "Separation and Distribution Agreement") with Knife River Corporation (formerly known as Knife River Holding Company) (“Knife River”). The Separation was structured

5-Year Revolving Credit Agreement, dated as of May 31, 2023, by and among MDU Resources Group, Inc., the financial institutions from time to time party thereto and U.S. Bank National Association.

Exhibit 10.5 $200,000,000 5-YEAR REVOLVING CREDIT AGREEMENT dated as of May 31, 2023 by and among MDU RESOURCES GROUP, INC., as Borrower, the Lenders referred to herein, as Lenders, and U.S. BANK NATIONAL ASSOCIATION, as Administrative Agent and COBANK, ACB JPMORGAN CHASE BANK, N.A. PNC BANK, NATIONAL ASSOCIATION and WELLS FARGO BANK, NATIONAL ASSOCIATION as Co-Syndication Agents U.S. BANK NATIONA

Term Loan Agreement, dated as of May 31, 2023, by and among MDU Resources Group, Inc., the lenders from time to time party thereto and U.S. Bank National Association.

Exhibit 10.7 $375,000,000 TERM LOAN AGREEMENT dated as of May 31, 2023 by and among MDU RESOURCES GROUP, INC., as Borrower, the Lenders referred to herein, as Lenders, and U.S. BANK NATIONAL ASSOCIATION, as Administrative Agent and COBANK, ACB JPMORGAN CHASE BANK, N.A. PNC BANK, NATIONAL ASSOCIATION and WELLS FARGO BANK, NATIONAL ASSOCIATION as Co-Syndication Agents U.S. BANK NATIONAL ASSOCIATION

364-Day Revolving Credit Agreement, dated as of May 31, 2023, by and among MDU Resources Group, Inc., the financial institutions from time to time party thereto and U.S. Bank National Association.

Exhibit 10.6 $150,000,000 364-DAY REVOLVING CREDIT AGREEMENT dated as of May 31, 2023 by and among MDU RESOURCES GROUP, INC., as Borrower, the Lenders referred to herein, as Lenders, and U.S. BANK NATIONAL ASSOCIATION, as Administrative Agent and COBANK, ACB JPMORGAN CHASE BANK, N.A. PNC BANK, NATIONAL ASSOCIATION and WELLS FARGO BANK, NATIONAL ASSOCIATION as Co-Syndication Agents U.S. BANK NATION

Employee Matters Agreement, dated as of May 30, 2023, by and between Knife River Corporation and MDU Resources Group, Inc.

Exhibit 10.3 EMPLOYEE MATTERS AGREEMENT BY AND BETWEEN MDU RESOURCES GROUP, INC. AND KNIFE RIVER HOLDING COMPANY DATED AS OF May 30, 2023 TABLE OF CONTENTS Page Article I DEFINITIONS Section 1.01 Definitions 1 Section 1.02 Interpretation 7 Article II GENERAL PRINCIPLES FOR ALLOCATION OF LIABILITIES Section 2.01 General Principles 7 Section 2.02 Service Credit Recognized by SpinCo and SpinCo Benefi

MDU Resources Completes Spinoff of Knife River

Exhibit 99.1 MDU Resources Completes Spinoff of Knife River BISMARCK, N.D. — June 1, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today announced that it has successfully completed the spinoff of its construction materials subsidiary, Knife River Corporation. As a result of the spinoff, Knife River is now an independent, public company that will begin “regular way” trading this morning on the New

Stockholder and Registration Rights Agreement, dated as of May 30, 2023, by and between Knife River Corporation and MDU Resources Group, Inc.^

Exhibit 10.4 STOCKHOLDER AND REGISTRATION RIGHTS AGREEMENT BY AND BETWEEN MDU RESOURCES GROUP, INC. AND KNIFE RIVER HOLDING COMPANY DATED AS OF MAY 30, 2023 TABLE OF CONTENTS Page TABLE OF CONTENTS i ARTICLE I DEFINITIONS 1 ARTICLE II REGISTRATION RIGHTS 6 Section 2.01 Registration 6 Section 2.02 Piggyback Registrations 10 Section 2.03 Registration Procedures 12 Section 2.04 Underwritten Offerings

Separation and Distribution Agreement, dated as of May 30, 2023, by and between Knife River Corporation and MDU Resources Group, Inc.

Exhibit 2.1 SEPARATION AND DISTRIBUTION AGREEMENT BY AND BETWEEN MDU RESOURCES GROUP, INC. AND KNIFE RIVER HOLDING COMPANY DATED AS OF MAY 30, 2023 TABLE OF CONTENTS Page ARTICLE I DEFINITIONS 2 1.1 Definitions 2 ARTICLE II THE SEPARATION 14 2.1 Transfer of Assets and Assumption of Liabilities 14 2.2 SpinCo Assets; Parent Assets 16 2.3 SpinCo Liabilities; Parent Liabilities 18 2.4 Approvals and No

Transition Services Agreement, dated as of May 30, 2023, by and between Knife River Corporation and MDU Resources Group, Inc.

Exhibit 10.1 TRANSITION SERVICES AGREEMENT by and between MDU Resources Group, Inc. and Knife river holding company dated as of May 30, 2023 TABLE OF CONTENTS Page ARTICLE I DEFINITIONS 2 Section 1.01. Definitions 2 ARTICLE II SERVICES 7 Section 2.01. Services 7 Section 2.02. Performance of Services 7 Section 2.03. Charges for Services 8 Section 2.04. Reimbursement for Out-of-Pocket Costs and Expe

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 30, 2023 MDU Resources Group

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 30, 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 N

Tax Matters Agreement, dated as of May 30, 2023, by and between Knife River Corporation and MDU Resources Group, Inc.

Exhibit 10.2 TAX MATTERS AGREEMENT DATED AS OF MAY 30, 2023 BY AND BETWEEN MDU RESOURCES GROUP, INC. AND KNIFE RIVER HOLDING COMPANY TABLE OF CONTENTS Page Section 1. Definition of Terms 2 Section 2. Allocation of Tax Liabilities 12 Section 2.01 General Rule 12 Section 2.02 Allocation of United States Federal Income Tax and Federal Other Tax 13 Section 2.03 Allocation of State Income Tax and State

Exhibit 1.01 - Conflict Minerals Report as required by Items 1.01 and 1.02 of this Form SD.

EX-1.01 2 a2023ex1-01conflictmineral.htm EX-1.01 Exhibit 1.01 MDU Resources Group, Inc. Conflict Minerals Report For The Year Ended December 31, 2022 Introduction This Conflict Minerals Report (the “Report”) has been prepared pursuant to Rule 13p-1 under the Securities Exchange Act of 1934 (the “Rule”), for the reporting period from January 1 to December 31, 2022. The Report relates to the process

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM SD SPECIALIZED DISCLOSURE REPORT MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) Delaware 1-03480 30-1133956 (State or other jurisdiction of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM SD SPECIALIZED DISCLOSURE REPORT MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) Delaware 1-03480 30-1133956 (State or other jurisdiction of Incorporation) (Commission File Number) (I.R.S. Employer Identification No.) 1200 West Century Avenue P.O. Box 5650 Bismarck, North Dakota 58506-5650

MDU / MDU Resources Group Inc / Corvex Management LP Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 4)* MDU RESOURCES GROUP, INC. (Name of Issuer) Common Stock, par value $1.00 per share (Title of Class of Securities) 552690109 (CUSIP Number) Keith Meister Patrick J. Dooley, Esq. Corvex Management LP 667 Madison Avenue New York, NY 10065 (212) 474-6700 COP

INFORMATION STATEMENT Knife River Holding Company Common Stock (par value $0.01 per share)

TABLE OF CONTENTS Exhibit 99.1   May 12, 2023 Dear MDU Resources Group, Inc. Stockholder: On August 4, 2022, we announced plans to separate our wholly owned subsidiary Knife River Corporation (“Knife River” or the “Company”) from MDU Resources Group, Inc. (“MDU Resources”). The separation will occur by means of a spinoff, intended to be tax-free, of a newly formed company named Knife River Holding

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 10, 2023 MDU Resources Group

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 10, 2023 MDU Resources Group Inc (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation) (Commission File Number) (I.R.S. Employer I

MDU Resources Announces Knife River Form 10 Registration Statement Declared Effective

Exhibit 99.2 MDU Resources Announces Knife River Form 10 Registration Statement Declared Effective BISMARCK, N.D. — May 12, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today announced that, in connection with the previously announced separation of Knife River Corporation from MDU Resources, the Securities and Exchange Commission has declared effective the Registration Statement on Form 10 filed b

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 9, 2023 MDU Resources Group

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 9, 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

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 ☐ TRANSITION REPORT PURSUANT TO

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP INC

MDU Resources Reports First Quarter Earnings; Board Approves Knife River Separation

MDU Resources Reports First Quarter Earnings; Board Approves Knife River Separation BISMARCK, N.

MDU Resources Declares Quarterly Dividend on Common Stock, Outlines Future Dividend Expectations

Exhibit 99.1 MDU Resources Declares Quarterly Dividend on Common Stock, Outlines Future Dividend Expectations BISMARCK, N.D. — May 4, 2023 —MDU Resources Group, Inc.’s (NYSE: MDU) board of directors has declared a quarterly dividend on the company’s common stock of 22.25 cents per share, unchanged from the previous quarter. The dividend is payable July 1 to stockholders of record June 13. MDU Reso

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, David L. Goodin, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the

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 3, 2023 MDU Resources Group

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 3, 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

Mine Safety Disclosures

MDU RESOURCES GROUP, INC. MINE SAFETY INFORMATION The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) requires issuers to include in periodic reports filed with the SEC certain information relating to citations or orders for violations of standards under the Federal Mine Safety and Health Act of 1977 (Mine Act), as amended by the Mine Improvement and New Emergency Respon

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 4, 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.

MDU Resources Board of Directors Approves Separation of Knife River; Declares Distribution of Shares for Knife River

EX-99.1 2 a2023ex99krcspinapproval.htm EX-99.1 Exhibit 99.1 MDU Resources Board of Directors Approves Separation of Knife River; Declares Distribution of Shares for Knife River BISMARCK, N.D. — May 4, 2023 — MDU Resources Group, Inc.’s (NYSE: MDU) board of directors has approved the previously announced separation of the company’s wholly owned construction materials subsidiary, Knife River Corpora

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 3, 2023 MDU Resources Group

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 3, 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

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): April 25, 2023 MDU Resources Gro

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): April 25, 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

MDU Resources Announces Closing of Knife River Holding Company’s $425 Million Notes Offering in Connection With Anticipated Knife River Spinoff

Exhibit 99.1 MDU Resources Announces Closing of Knife River Holding Company’s $425 Million Notes Offering in Connection With Anticipated Knife River Spinoff BISMARCK, N.D. — April 25, 2023 — MDU Resources Group, Inc. (“MDU Resources”) (NYSE: MDU) today announced the closing of its previously announced offering of $425 million of notes due 2031 (the “notes”) by Knife River Holding Company, a wholly

MDU / MDU Resources Group Inc / Corvex Management LP - SC 13D/A Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 3)* MDU RESOURCES GROUP, INC. (Name of Issuer) Common Stock, par value $1.00 per share (Title of Class of Securities) 552690109 (CUSIP Number) Keith Meister Patrick J. Dooley, Esq. Corvex Management LP 667 Madison Avenue New York, NY 10065 (212) 474-6700 COP

MDU Resources Announces Pricing of Knife River Holding Company’s $425 Million Notes Offering in Connection With Anticipated Knife River Spinoff

Exhibit 99.1 MDU Resources Announces Pricing of Knife River Holding Company’s $425 Million Notes Offering in Connection With Anticipated Knife River Spinoff BISMARCK, N.D. — April 11, 2023 — MDU Resources Group, Inc. (“MDU Resources”) (NYSE: MDU) today announced that Knife River Holding Company, a wholly owned subsidiary of MDU Resources, has priced an offering of $425 million of notes due 2031, i

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): April 11, 2023 MDU Resources Gro

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): April 11, 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

MDU Resources Announces Launch of Knife River Holding Company’s Notes Offering in Connection With Anticipated Knife River Spinoff

Exhibit 99.1 MDU Resources Announces Launch of Knife River Holding Company’s Notes Offering in Connection With Anticipated Knife River Spinoff BISMARCK, N.D. — April 10, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today announced that Knife River Holding Company, a wholly owned subsidiary of MDU Resources, has launched an offering of notes due 2031, subject to market conditions and other customar

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): April 10, 2023 MDU Resources Gro

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): April 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

MDU Resources Announces Anticipated Board of Directors for Knife River

Exhibit 99.1 MDU Resources Announces Anticipated Board of Directors for Knife River BISMARCK, N.D. — April 7, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today announced the anticipated board of directors for Knife River Holding Company, effective upon completion of the planned separation of MDU Resources’ construction materials subsidiary into an independent, publicly traded company. The separat

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): April 7, 2023 MDU Resources Grou

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): April 7, 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

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ý Filed by a party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ý Filed by a party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

Restricted Stock Unit Award Agreement under the Long-Term Performance-Based Incentive Plan, as amended February 16, 2023

MDU RESOURCES GROUP, INC. RESTRICTED STOCK UNIT AWARD NOTICE This Award Notice evidences the award of restricted stock units (each, an “RSU” or collectively, the “RSUs”) that have been granted to, ( ), by MDU Resources Group, Inc., a Delaware corporation (the “Company”), subject to your acceptance of the terms of this Award Notice, the Restricted Stock Unit Award Agreement, which is attached heret

David C. Barney Offer Letter, dated February 17, 2023

February 17, 2023 Dave C. Barney Re: Senior Advisor Role I am pleased to offer you the non-executive position of Senior Advisor at Knife River Corporation (“KRC") effective March 1, 2023. In this position, you will support an orderly transition of your duties and responsibilities to your successor as President and CEO of KRC. You will be called upon to provide such assistance and services as are r

Subsidiaries of MDU Resources Group, Inc.

MDU RESOURCES GROUP, INC. List of Subsidiaries (effective December 31, 2022) Subsidiaries Jurisdiction of Formation Alaska Basic Industries, Inc. Alaska Ames Sand & Gravel, Inc. North Dakota Anchorage Sand and Gravel Company, Inc. Alaska ARC Fabricators, L.L.C. South Dakota Baldwin Contracting Company, Inc. California Bell Electrical Contractors, Inc. Missouri Bombard Electric, LLC Nevada Bombard

Retention Agreement for Jeffrey S. Thiede, dated February 17, 2023

RETENTION AGREEMENT This Retention Agreement (“Agreement”) is made and entered into effective as of this 17th day of February, 2023 (the “Effective Date”), by and between Jeffrey S.

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, David L. Goodin, certify that: 1.I have reviewed this annual report on Form 10-K of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the pe

MDU Resources Group, Inc. Section 16 Officers and Directors with Indemnification Agreements Chart, as of February 1, 2023

MDU Resources Group, Inc. Section 16 Officers and Directors with Indemnification Agreements Chart As of February 1, 2023 Section 16 Officers Name Title Date of Agreement David L. Goodin President and Chief Executive Officer, MDU Resources Group, Inc. August 12, 2010, as amended May 15, 2014 David C. Barney Chief Executive Officer, Knife River Corporation May 16, 2013, as amended May 15, 2014 Steph

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 ☐ TRANSITION REPORT PURSUANT TO SECTI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP INC (Exa

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this annual report on Form 10-K of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the p

WBI Energy Transmission, Inc. Second Amendment and Restatement Note Purchase and Private Shelf Agreement, effective as of December 22, 2022, among Prudential Investment Management, Inc. and certain investors described therein

WBI ENERGY TRANSMISSION, INC. $350,000,000 Private Shelf Facility Including: $25,000,000 4.61% Senior Notes, Series D, due 2028 $20,000,000 4.48% Senior Notes, Series E, due 2025 $40,000,000 4.91% Senior Notes, Series F, due 2031 $40,000,000 4.18% Senior Notes, Series G, due 2033 $45,000,000 4.17% Senior Notes, Series H, due 2034 $25,000,000 3.26% Senior Notes, Series I, due 2035 $40,000,000 6.67%

Mine Safety Disclosures

MDU RESOURCES GROUP, INC. MINE SAFETY INFORMATION The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) requires issuers to include in periodic reports filed with the SEC certain information relating to citations or orders for violations of standards under the Federal Mine Safety and Health Act of 1977 (Mine Act), as amended by the Mine Improvement and New Emergency Respon

Fifth Amendment to MDU Resources Group, Inc. 401(k) Retirement Plan, as amended December 28, 2022

FIFTH AMENDMENT TO MDU RESOURCES GROUP, INC. 401(k) RETIREMENT PLAN The MDU Resources Group, Inc. 401(k) Retirement Plan (the “Plan”), as most recently amended and restated effective April 1, 2020, is hereby amended by this Fifth Amendment effective as of August 18, 2014. All terms defined in the Plan shall have the same meanings when used herein. 1.Section A-12 shall be amended to read as follows

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): February 16, 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 Identificat

Financial Statements and Exhibits, Other Events

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): February 16, 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 Identificat

MDU Resources Board of Directors Names Leadership for Knife River Upon Separation

Exhibit 99.1 MDU Resources Board of Directors Names Leadership for Knife River Upon Separation BISMARCK, N.D. — Feb. 16, 2023 — MDU Resources Group, Inc.’s (NYSE: MDU) board of directors has selected the management team who will lead Knife River Corporation, the company’s construction materials subsidiary, effective upon completion of the anticipated separation of Knife River into an independent,

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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) February 9, 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 Identificatio

MDU / Mdu Resources Group Inc / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SC 13G/A 1 tv0081-mduresourcesgroupinc.htm SCHEDULE 13G/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 11)* Name of issuer: MDU Resources Group Inc. Title of Class of Securities: Common Stock CUSIP Number: 552690109 Date of Event Which Requires Filing of this Statement: December 30, 2022 Check the appropriate box t

MDU Resources Reports 2022 Earnings; Initiates 2023 Guidance

EX-99 2 a2022earningsreleaseex-99.htm MDU RESOURCES GROUP, INC. EX 99 MDU Resources Reports 2022 Earnings; Initiates 2023 Guidance BISMARCK, N.D. — Feb. 9, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today reported 2022 earnings on a generally accepted accounting principles (GAAP) basis of $367.5 million, or $1.81 per share, with adjusted earnings of $380.2 million, or $1.87 per share, compared t

Cooperation Agreement, dated as of January 24, 2023, by and among Keith A. Meister, Corvex Management LP and MDU Resources Group, Inc.

Exhibit 10.1 This COOPERATION AGREEMENT (this “Agreement”), dated as of January 24, 2023, is by and among Keith A. Meister, Corvex Management LP (Mr. Meister and Corvex Management LP, together with their respective affiliates, the “Corvex Group”) and MDU Resources Group, Inc. (the “Company”). NOW, THEREFORE, in consideration of and reliance upon the mutual covenants and agreements contained herein

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

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): January 24, 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 Identificati

MDU / Mdu Resources Group Inc / Corvex Management LP Activist Investment

SC 13D/A 1 formsc13da-mdu.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 2)* MDU RESOURCES GROUP, INC. (Name of Issuer) Common Stock, par value $1.00 per share (Title of Class of Securities) 552690109 (CUSIP Number) Keith Meister Patrick J. Dooley, Esq. Corvex Management LP 667 Madison Avenue New Yor

MDU Resources Enters Into Cooperation Agreement With Corvex Management

Exhibit 99.1 MDU Resources Enters Into Cooperation Agreement With Corvex Management BISMARCK, N.D. — Jan. 24, 2023 — MDU Resources Group, Inc. (NYSE: MDU) today announced that it has entered into a cooperation agreement with Corvex Management LP under which Corvex Partner James H. Gemmel will be appointed to MDU Resources’ board of directors, subject to approval by the Federal Energy Regulatory Co

Financial Statements and Exhibits, Other Events

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): December 14, 2022 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 Identificat

MDU Resources Expects Second Quarter Spinoff of Knife River Corp.; Strategic Review of MDU Construction Services Group Underway

Exhibit 99.1 MDU Resources Expects Second Quarter Spinoff of Knife River Corp.; Strategic Review of MDU Construction Services Group Underway BISMARCK, N.D. ? Dec. 15, 2022 ? MDU Resources Group, Inc. (NYSE: MDU) on Wednesday submitted a confidential draft registration statement on Form 10 with the U.S. Securities and Exchange Commission in connection with the planned spinoff of its construction ma

Regulation FD Disclosure, Financial Statements and Exhibits

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) November 22, 2022 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 Identificati

MDU Resources Announces Five-Year Capital Investment Plan

MDU Resources Announces Five-Year Capital Investment Plan BISMARCK, N.D. ? Nov. 22, 2022 ? MDU Resources Group, Inc. (NYSE: MDU) today announced its plans to make capital investments totaling $3.5 billion over the five-year period from 2023 to 2027. ?Our capital investment plan includes a number of key projects that are expected to provide organic growth across our businesses, with particular emph

MDU Resources Appoints German Carmona Alvarez to Board of Directors

Exhibit 99.1 MDU Resources Appoints German Carmona Alvarez to Board of Directors BISMARCK, N.D. ? Nov. 18, 2022 ? MDU Resources Group, Inc. (NYSE: MDU) today announced that German Carmona Alvarez has been appointed to the company?s board of directors. Carmona is global president, applied intelligence, at John Wood Group PLC, which provides consulting, project management and engineering solutions t

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): November 17, 2022 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 Identificat

MDU Resources Names Brian Gray President of Knife River Corporation; David Barney Remains CEO

EX-99.1 2 exhibit99gray.htm EX-99.1 Exhibit 99.1 MDU Resources Names Brian Gray President of Knife River Corporation; David Barney Remains CEO BISMARCK, N.D. — Nov. 17, 2022 — The Board of Directors of MDU Resources Group, Inc. (NYSE: MDU) today announced that Brian R. Gray has been named president of the company’s wholly owned construction materials subsidiary, Knife River Corporation, effective

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): November 17, 2022 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 Identificat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 ☐ TRANSITION REPORT PURSUANT

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, David L. Goodin, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the

Fourth Amendment to MDU Resources Group, Inc. 401(k) Retirement Plan, as amended August 17, 2022

FOURTH AMENDMENT TO THE MDU RESOURCES GROUP, INC. 401(k) RETIREMENT PLAN The MDU Resources Group, Inc. 401(k) Retirement Plan (the ?Plan?), as most recently amended and restated effective April 1, 2020 is hereby further amended by this Fourth Amendment effective as of January 1, 2022, as follows: By adding the following paragraphs in Section C.1-2 Eligibility of Schedule C.1 Retirement Contributio

Mine Safety Disclosures

MDU RESOURCES GROUP, INC. MINE SAFETY INFORMATION The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) requires issuers to include in periodic reports filed with the SEC certain information relating to citations or orders for violations of standards under the Federal Mine Safety and Health Act of 1977 (Mine Act), as amended by the Mine Improvement and New Emergency Respon

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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) November 3, 2022 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 Identificatio

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

MDU / Mdu Resources Group Inc / Corvex Management LP Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. 1)* MDU RESOURCES GROUP, INC. (Name of Issuer) Common Stock, par value $1.00 per share (Title of Class of Securities) 552690109 (CUSIP Number) Keith Meister Patrick J. Dooley, Esq. Corvex Management LP 667 Madison Avenue New York, NY 10065 (212) 474-6700 COP

MDU Resources Reports Third Quarter Earnings; Board Authorizes Strategic Review for MDU Construction Services Group

MDU Resources Reports Third Quarter Earnings; Board Authorizes Strategic Review for MDU Construction Services Group BISMARCK, N.

MDU / Mdu Resources Group Inc / Corvex Management LP Activist Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 (Amendment No. )* MDU RESOURCES GROUP INC. (Name of Issuer) Common Stock, par value $1.00 per share (Title of Class of Securities) 552690109 (CUSIP Number) Keith Meister Patrick J. Dooley, Esq. Corvex Management LP 667 Madison Avenue New York, NY 10065 (212) 474-6700 COPIE

MDU Resource Group, Inc. Director Compensation Policy, as amended May 11, 2022

MDU RESOURCES GROUP, INC. DIRECTOR COMPENSATION POLICY Each director of MDU Resources Group, Inc. (the ?Company?) who is not a full-time employee of the Company (a ?Director?) shall receive compensation made up of annual cash retainers and shares of the Company?s common stock (?Common Stock?), as set forth in this policy. Director Compensation Annual Cash Retainers Base Retainer $110,000* Addition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 ☐ TRANSITION REPORT PURSUANT TO S

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP INC

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, David L. Goodin, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the

Mine Safety Disclosures

MDU RESOURCES GROUP, INC. MINE SAFETY INFORMATION The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) requires issuers to include in periodic reports filed with the SEC certain information relating to citations or orders for violations of standards under the Federal Mine Safety and Health Act of 1977 (Mine Act), as amended by the Mine Improvement and New Emergency Respon

MDU Resources Announces Plan to Separate Knife River, Creating Two Focused, Independent Publicly Traded Companies

MDU Resources Announces Plan to Separate Knife River, Creating Two Focused, Independent Publicly Traded Companies ?Spinoff of Knife River expected to unlock significant shareholder value.

Regulation FD Disclosure, Financial Statements and Exhibits

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 4, 2022 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

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 4, 2022 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

MDU Resources Reports Second Quarter Earnings, Revises Earnings Guidance

MDU Resources Reports Second Quarter Earnings, Revises Earnings Guidance BISMARCK, N.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K ý ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 o TRANSITION REPORT PURSUANT TO SECTION 15(

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 11-K ? ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR o TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP, INC. 401(k) RETIREM

Exhibit 1.01 - Conflict Minerals Report as required by Items 1.01 and 1.02 of this Form SD.

Exhibit 1.01 MDU Resources Group, Inc. Conflict Minerals Report For The Year Ended December 31, 2021 Introduction This Conflict Minerals Report (the ?Report?) has been prepared pursuant to Rule 13p-1 under the Securities Exchange Act of 1934 (the ?Rule?), for the reporting period from January 1 to December 31, 2021. The Report relates to the process undertaken by MDU Resources Group, Inc. (herein

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM SD SPECIALIZED DISCLOSURE REPORT MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) Delaware 1-03480 30-1133956 (State or other jurisdiction of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM SD SPECIALIZED DISCLOSURE REPORT MDU Resources Group, Inc. (Exact name of registrant as specified in its charter) Delaware 1-03480 30-1133956 (State or other jurisdiction of Incorporation) (Commission File Number) (I.R.S. Employer Identification No.) 1200 West Century Avenue P.O. Box 5650 Bismarck, North Dakota 58506-5650

May 16, 2022

May 16, 2022 VIA EDGAR Ms. Diane Fritz; Ms. Kimberly Calder; Mr. John Coleman Division of Corporation Finance Office of Energy & Transportation U.S. Securities and Exchange Commission 100 F Street, N.E. Washington, D.C. 20549 Re: MDU Resources Group, Inc. Form 10-K for the Fiscal Year Ended December 31, 2021 Filed February 23, 2022 File No. 001-03480 Dear Ms. Fritz, Ms. Calder and Mr. Coleman: On

Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

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 10, 2022 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 N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 ☐ TRANSITION REPORT PURSUANT TO

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 1-03480 MDU RESOURCES GROUP INC

Certification of Chief Executive Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, David L. Goodin, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this quarterly report on Form 10-Q of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to th

Mine Safety Disclosures

MDU RESOURCES GROUP, INC. MINE SAFETY INFORMATION The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) requires issuers to include in periodic reports filed with the SEC certain information relating to citations or orders for violations of standards under the Federal Mine Safety and Health Act of 1977 (Mine Act), as amended by the Mine Improvement and New Emergency Respon

MDU Resources Reports First Quarter Earnings, Affirms EPS Guidance

MDU Resources Reports First Quarter Earnings, Affirms EPS Guidance BISMARCK, N.D. ? May 4, 2022 ? MDU Resources Group, Inc. (NYSE: MDU) today reported first quarter earnings of $31.7 million, or 16 cents per share, compared to first quarter 2021 earnings of $52.1 million, or 26 cents per share. ?We have a solid start to the year with higher revenues at all our businesses, including record revenues

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

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 4, 2022 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.

April 26, 2022

April 26, 2022 VIA EDGAR AND OVERNIGHT DELIVERY Ms. Diane Fritz; Ms. Kimberly Calder; Mr. John Coleman Division of Corporation Finance Office of Energy & Transportation U.S. Securities and Exchange Commission 100 F Street, N.E. Washington, D.C. 20549 Re: MDU Resources Group, Inc. Form 10-K for the Fiscal Year Ended December 31, 2021 Filed February 23, 2022 File No. 001-03480 Dear Ms. Fritz, Ms. Ca

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ? Filed by a party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ? Filed by a party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

MDU Resources Group, Inc. 401(k) Retirement Plan, as amended January 1, 2022

THIRD AMENDMENT TO MDU RESOURCES GROUP, INC. 401(k) RETIREMENT PLAN The MDU Resources Group, Inc. 401(k) Retirement Plan (the ?Plan?), as most recently amended and restated effective April 1, 2020, is hereby further amended by this Third Amendment effective January 1, 2022, except as otherwise specified herein. All terms defined in the Plan shall have the same meanings when used herein. 1.Section

Certification of Chief Financial Officer filed pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

CERTIFICATION I, Jason L. Vollmer, certify that: 1.I have reviewed this annual report on Form 10-K of MDU Resources Group, Inc.; 2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the p

Mine Safety Disclosures

MDU RESOURCES GROUP, INC. MINE SAFETY INFORMATION The Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank Act) requires issuers to include in periodic reports filed with the SEC certain information relating to citations or orders for violations of standards under the Federal Mine Safety and Health Act of 1977 (Mine Act), as amended by the Mine Improvement and New Emergency Respon