Form 8-K

8-K — MDU RESOURCES GROUP INC

Accession: 0000067716-26-000064

Filed: 2026-08-06

Period: 2026-08-06

CIK: 0000067716

SIC: 1400 (MINING, QUARRYING OF NONMETALLIC MINERALS (NO FUELS))

Item: Results of Operations and Financial Condition

Item: Regulation FD Disclosure

Item: Financial Statements and Exhibits

Documents

8-K — mdu-20260806.htm (Primary)

EX-99 — MDU RESOURCES EX 99 EARNINGS RELEASE (a2026q2ex99.htm)

GRAPHIC — MDU RESOURCES LOGO HEADER (header01.jpg)

XML — IDEA: XBRL DOCUMENT (R1.htm)

8-K — MDU RESOURCES FORM 8-K EARNINGS RELEASE

8-K (Primary)

Filename: mdu-20260806.htm · Sequence: 1

mdu-20260806

0000067716false00000677162026-08-062026-08-06

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 6, 2026

MDU Resources Group, Inc.

(Exact name of registrant as specified in its charter)

Delaware 1-03480 30-1133956

(State or other jurisdiction of (Commission File Number) (IRS Employer

incorporation) Identification No.)

1200 West Century Avenue

P.O. Box 5650

Bismarck, North Dakota

(Address of principal executive offices)

58506

(Zip Code)

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

N/A

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

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Securities Exchange Act of 1934::

Title of each class Trading Symbol(s) Name of each exchange on which registered

Common Stock, par value $1.00 per share MDU New York Stock Exchange

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 or Rule 12b-2 of the Securities Exchange Act of 1934.

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 2.02. Results of Operations and Financial Condition.

On August 6, 2026, MDU Resources Group, Inc. (the “Company”) issued a news release (the “News Release”) announcing its financial results for the second quarter of 2026. A copy of the News Release is furnished as Exhibit 99 to this Current Report on Form 8-K, which, in its entirety, is incorporated herein by reference.

The Company is webcasting a conference call on August 6, 2026, to discuss its second quarter 2026 financial results, during which the Company will provide an update on the business.

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

Item 7.01. Regulation FD Disclosure.

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

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

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

Exhibit No.

Description

News Release, dated August 6, 2026.

104

Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURE

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

MDU Resources Group, Inc.

Date: August 6, 2026

By: /s/ Jason L. Vollmer

Jason L. Vollmer

Chief Financial Officer

EX-99 — MDU RESOURCES EX 99 EARNINGS RELEASE

EX-99

Filename: a2026q2ex99.htm · Sequence: 2

Document

MDU Resources Reports Second Quarter 2026 Results; Advances Infrastructure

Growth Opportunities

•Consolidated net income of $21.3 million, up 55.5% from the same quarter last year

•Earnings per share of $0.10, up 42.9% year-over-year

•Continued progress on proposed Bakken East Pipeline Project

•2026 guidance reaffirmed; earnings per share in the range of $0.93 to $1.00

BISMARCK, N.D.—Aug. 6, 2026—MDU Resources Group, Inc. (NYSE: MDU) today announced its financial results for the second quarter of 2026, highlighting continued execution across its regulated utility and pipeline businesses, progress on key growth initiatives and increasing infrastructure opportunities driven by customer growth and emerging demand trends.

"We delivered solid second quarter results while continuing to position the company for long-term growth," said Nicole A. Kivisto, president and CEO of MDU Resources. "Our utility businesses benefited from new rates, customer growth and investments such as Badger Wind Farm, while our pipeline business continued advancing strategic projects that have the potential to create meaningful value over time. We are especially encouraged by the continued advancement of our proposed Bakken East Pipeline Project. We believe our progress with customer commitments demonstrates the project's strategic value. We also remain encouraged by development activity across our service territory, including data center opportunities and growing infrastructure demand."

The following summarizes the company's results for the three and six months ended June 30:

Three Months Ended June 30:

Six Months Ended June 30:

2026 2025 2026 2025

(In millions, except per share amounts)

Net income $ 21.3 $ 13.7 $ 102.1 $ 95.7

Earnings per share, diluted $ .10 $ .07 $ .49 $ .47

"Our employees continue to demonstrate a commitment to safety, reliability, operational excellence and customer service," Kivisto added. "Their efforts are helping us navigate a dynamic operating environment while advancing important infrastructure investments that support customers and communities.

Proposed Bakken East Pipeline Project Update

The proposed Bakken East Pipeline Project continues to advance through engineering, environmental review and pre-filing activities. With recently signed precedent agreements, we now have executed agreements with all customers that submitted binding open season interest totaling nearly 1.2 billion cubic feet per day of firm natural gas transportation capacity, with a negotiated option in place that may increase the contracted volumes to nearly all of the original interest from our binding open season. The company continues to design the project for 1.4 billion cubic feet per day of transportation capacity. Overall project design is being finalized based on confirmed customer volumes and delivery locations before a final investment decision is made, which is expected ahead of a FERC Section 7(c) application.

This application is now anticipated to be filed in the fourth quarter of 2026. The proposed in-service dates of Phase One in late 2029 and Phase Two in late 2030, remain. As development progresses, the company continues to evaluate all financing options to support the projected $2.7 billion to $3.2 billion project.

Electric Utility Segment

Strong earnings growth driven by Badger Wind recovery, implementation of new and interim rates and increased volumes

•Badger Wind Farm contributed $3.3 million in earnings for the quarter

•Montana interim rates and new Wyoming electric rates contributed positively to results

•Retail sales volumes increased 8.2%

The electric segment earned $14.7 million in the second quarter of 2026, compared with $10.4 million in the second quarter of 2025. In addition to Badger Wind Farm, results benefited from implemented rate increases and higher retail sales volumes. Data center demand continued to contribute to electric retail sales volume growth.

Approach to Data Centers

Our approach to serving data center customers, is grounded in protecting existing customers and ensuring that growth creates value for the communities we serve. Data center customers are responsible for paying the costs associated with connecting to and being served by the electric system, including infrastructure and energy-related expenses. Through careful planning, regulatory oversight and cost-allocation mechanisms, we ensure that existing customers are not subsidizing the costs of serving these new customers. At the same time, the additional revenue generated from serving data center customers can help support the electric system and contribute to reducing certain fixed costs by allocating them across a broader customer base. This current approach creates benefits for all customers.

Regulatory Update:

•North Dakota:

◦Filed an electric general rate case on June 30, 2026, requesting an annual revenue

increase of approximately $34.5 million. Interim rates of approximately $26.3 million have been requested beginning Sept. 1, 2026. The filing reflects investments in electric infrastructure, normal depreciation of those assets, reliability improvements, system safety and higher operation and maintenance expense.

◦Entered into an electric service agreement (ESA) in June with Applied Digital Corp. to serve Polaris Forge 3, an AI Factory near Center, North Dakota. At full capacity, the campus would require 430 megawatts of electricity. Approval of the ESA and other regulatory filings by the North Dakota Public Service Commission is pending.

◦In June, the North Dakota Public Service Commission approved the route permit for the Jamestown-to-Ellendale Transmission Project (JETx). The project is expected to enhance reliability, improve resiliency, reduce transmission congestion and support access to lower-cost energy across the region.

•Montana: Interim electric rates reflecting an annual increase of approximately $10.4 million remain in effect, subject to refund. A settlement agreement of $10.0 million has been filed and is pending approval by the Montana Public Service Commission.

•Wyoming: General rate case settlement was approved for an annual increase of $5.8 million with rates effective April 1, 2026; reflecting recovery of infrastructure investments as well as associated operation and maintenance expense.

Natural Gas Distribution Segment

New rates and higher retail sales volumes support improved year-over-year results, offset by interest expense increases

•Positive contributions from new rates in Idaho, Washington, Montana and Wyoming

•Retail sales volumes increased 6.7%

•Continued customer growth of 1.6% year-over-year

•Increased interest expense due to higher long-term debt balances

The natural gas distribution segment reported a seasonal second quarter loss of $3.9 million, compared with a seasonal loss of $7.4 million in the prior-year period. Results benefited from new rates across multiple jurisdictions, increased retail sales volumes and continued customer growth. The higher interest expense partially offset the gains.

Regulatory Update:

•Washington: Filed a multiyear natural gas rate case with the Washington Utilities and Transportation Commission requesting an annual revenue increase of $25.1 million in year one, and $18.1 million in year two. The filing reflects investments in natural gas infrastructure, reliability improvements, system safety and normal depreciation of those assets. The request is pending a decision by the commission.

•Oregon: A multi-party settlement agreement of $12.2 million has been filed and is pending approval by the Oregon Public Utility Commission.

•Minnesota: General rate case filing is anticipated later this year.

Pipeline Segment

Strategic growth initiatives continue to advance

•Continued development of the proposed Bakken East Pipeline Project

•Progress on additional growth projects

•Strong transportation demand across the system

The pipeline segment earned approximately $14.4 million in the second quarter of 2026, compared with $15.4 million in the second quarter of 2025. Results were driven by lower other income and higher depreciation expense. These impacts were partially offset by increased transportation revenue, primarily due to customer demand for short-term natural gas transportation contracts.

Strategic Project Updates:

•Proposed Bakken East Pipeline Project: Development activities continued during the quarter as the company advanced customer agreements, engineering work and regulatory activities. We have executed precedent agreements totaling nearly 1.2 billion cubic feet per day, with a negotiated option in place for nearly all of the original interest from our binding open season. The company continues engineering, environmental, cultural resource and stakeholder engagement activities while evaluating financing and partnership opportunities. Development activities remain focused on creating long-term value while advancing a strategically significant infrastructure project for North Dakota and the broader region.

•Line Section 32 Expansion Project: The project remains on schedule following the filing of a FERC 7(c) application in March 2026. The filing represents an important regulatory milestone as the project advances toward its targeted late-2028 in-service date, subject to regulatory approvals.

•Minot Industrial Project: Development activities for this potential project continue under agreements currently extended through late 2026. The proposed project could consist of an approximately 90-mile pipeline from Tioga, North Dakota to Minot, North Dakota and ancillary facilities to support anticipated industrial demand in the area.

Regulatory Update:

•FERC rate case filed on May 29, 2026, requesting updated transportation and storage services rates. The filing seeks a $31 million annual revenue increase. Approximately 30% of the requested revenue increase is due to proposed new depreciation and amortization rates. FERC

accepted and suspended the proposed rates on June 30, 2026, with rates to become effective Dec. 1, 2026, subject to refund and the outcome of hearing procedures if a settlement with our customers and FERC is not reached.

Guidance

MDU Resources is reaffirming guidance and expects earnings per share to be in the range of $0.93 to $1.00.

The expected 2026 results are based on several assumptions, including normal weather, economic and operating conditions for the remainder of the year, continued customer growth, successful execution of approved capital investment programs and constructive regulatory outcomes.

The company's long-term earnings-per-share growth objective remains 6% to 8%.

Conference Call

MDU Resources will webcast its second quarter 2026 earnings conference call today at 2 p.m. ET. The webcast can be accessed through the Investors section of the company's website. A replay will be available following the call.

About MDU Resources Group, Inc.

MDU Resources Group, Inc., a member of the S&P SmallCap 600 index, strives to deliver safe, reliable, cost-effective and environmentally responsible electric utility and natural gas distribution services to more than 1.2 million customers across the Pacific Northwest and Midwest. In addition to its utility operations, the company’s pipeline business operates a more than 3,800-mile natural gas pipeline network and storage system, ensuring reliable energy delivery across the Northern Plains. With a legacy spanning over a century, MDU Resources remains focused on energizing lives for a better tomorrow. For more information about MDU Resources, visit www.mdu.com or contact the investor relations department at investor@mduresources.com.

Investor Contact: Brent Miller, treasurer, 701-530-1730

Media Contact: Byron Pfordte, director of integrated communications, 208-377-6050

Cautionary Note Regarding Forward-Looking Statements

This news release contains forward-looking statements within the meaning of the federal securities laws.

Other than statements of historical facts, all statements which address activities, events or developments that the company anticipates will or may occur in the future are forward-looking statements based on underlying assumptions (many of which are based, in turn, upon further assumptions), including but not limited to, statements identified by the words "anticipates," "estimates," "expects," "intends," "plans," and "predicts," in each case related to such things as growth estimates, stockholder value creation, the company's "CORE" strategy, capital expenditures, financial guidance, trends, objectives, goals, dividend payout ratio targets, earnings per share growth targets, customer rates, regulatory approvals, sustainability, strategies and other such matters. These forward-looking statements are based on many assumptions and factors, which are detailed in the company's filings with the U.S. Securities and Exchange Commission.

While made in good faith, these forward-looking statements are based largely on the company's

expectations and judgments and are subject to a number of risks and uncertainties, many of which are

unforeseeable and beyond the company's control. For additional discussion regarding risks and

uncertainties that may affect forward-looking statements, see "Risk Factors" disclosed in the company's

most recent Annual Report on Form 10-K, and subsequent filings. Any changes in such assumptions or

factors could produce significantly different results. Undue reliance should not be placed on forward-looking statements, which speak only as of the date they are made. Except as required by applicable law, the company undertakes no obligation to update the forward-looking statements, whether as a result of new information, future events or otherwise.

Consolidated Statements of Income

Three Months Ended Six Months Ended

June 30, June 30,

2026 2025 2026 2025

(In millions, except per share amounts)

(Unaudited)

Operating revenues $ 375.2 $ 351.2 $ 981.2 $ 1,026.0

Operating expenses:

Purchased natural gas sold 93.5 96.0 332.9 413.2

Electric fuel and purchased power 38.6 34.9 84.7 78.6

Operation and maintenance 114.1 112.8 228.9 223.9

Depreciation and amortization 55.2 51.8 109.4 103.1

Taxes, other than income 25.9 25.3 61.7 64.0

Total operating expenses 327.3 320.8 817.6 882.8

Operating income 47.9 30.4 163.6 143.2

Other income 6.2 9.9 8.8 14.9

Interest expense 31.5 25.4 64.2 52.2

Income before income taxes 22.6 14.9 108.2 105.9

Income tax expense 3.3 .8 8.0 9.3

Income from continuing operations 19.3 14.1 100.2 96.6

Discontinued operations, net of tax 2.0 (.4) 1.9 (.9)

Net income $ 21.3 $ 13.7 $ 102.1 $ 95.7

Earnings per share – basic:

Income from continuing operations $ .09 $ .07 $ .48 $ .47

Discontinued operations, net of tax .01 — .01 —

Earnings per share – basic $ .10 $ .07 $ .49 $ .47

Earnings per share – diluted:

Income from continuing operations $ .09 $ .07 $ .48 $ .47

Discontinued operations, net of tax .01 — .01 —

Earnings per share – diluted $ .10 $ .07 $ .49 $ .47

Weighted average common shares outstanding – basic 209.6 204.3 207.5 204.2

Weighted average common shares outstanding – diluted 211.7 205.2 209.3 205.1

Selected Cash Flows Information

Six Months Ended

June 30,

2026 2025

(In millions)

Net cash provided by operating activities $ 265.3 $ 334.9

Net cash used in investing activities (196.1) (174.4)

Net cash used in financing activities (51.1) (168.6)

Increase (decrease) in cash, cash equivalents and restricted cash 18.1 (8.1)

Cash, cash equivalents and restricted cash - beginning of year 28.2 66.9

Cash, cash equivalents and restricted cash - end of period $ 46.3 $ 58.8

Capital Expenditures

Business Line

2026 Estimated

2027 Estimated

2028 Estimated

2029 Estimated

2030 Estimated

2026-2030 Total Estimated

(In millions)

Electric $ 129 $ 309 $ 250 $ 184 $ 210 $ 1,082

Natural gas distribution 340 295 240 254 223 1,352

Pipeline 60 70 181 282 50 643

Total capital expenditures1

$ 529 $ 674 $ 671 $ 720 $ 483 $ 3,077

1 Excludes Other category

Note: Total capital expenditures is presented on a net basis

The capital program is subject to continued review and modification by the company. Actual expenditures may vary from estimates. Investment in the potential Bakken East Pipeline project would be incremental to the outlined capital program.

Electric Three Months Ended Six Months Ended

June 30, June 30,

2026 2025 2026 2025

(In millions)

Operating revenues1,2

$ 116.1 $ 98.1 $ 237.3 $ 210.5

Operating expenses:

Electric fuel and purchased power1

38.6 34.9 84.7 78.6

Operation and maintenance 31.2 29.9 60.1 58.5

Depreciation and amortization 20.3 17.4 39.9 34.6

Taxes, other than income 5.4 4.7 10.9 9.5

Total operating expenses 95.5 86.9 195.6 181.2

Operating income 20.6 11.2 41.7 29.3

Other income 1.9 2.7 2.3 3.7

Interest expense 11.2 7.6 23.1 15.5

Income before income taxes 11.3 6.3 20.9 17.5

Income tax benefit2

(3.4) (4.1) (8.3) (7.9)

Net income $ 14.7 $ 10.4 $ 29.2 $ 25.4

Operating Statistics Three Months Ended Six Months Ended

June 30, June 30,

2026 2025 2026 2025

Revenues (millions)1,2

Retail sales:

Residential $ 35.3 $ 28.3 $ 74.4 $ 66.5

Commercial3

48.8 41.2 95.7 86.4

Industrial 11.0 9.1 20.9 17.9

Other 2.0 1.8 4.0 3.5

97.1 80.4 195.0 174.3

Other 19.0 17.7 42.3 36.2

$ 116.1 $ 98.1 $ 237.3 $ 210.5

Volumes (million kWh)

Retail sales:

Residential 253.4 235.8 585.4 606.5

Commercial3

732.1 672.7 1,474.0 1,396.6

Industrial 128.7 120.0 249.4 236.7

Other 20.1 20.1 39.3 40.3

1,134.3 1,048.6 2,348.1 2,280.1

Average cost of electric fuel and purchased power per kWh $ .026 $ .024 $ .027 $ .025

The previous tables reflect items that are passed through to customers resulting in minimal impact to earnings. These items include:

1 Electric fuel and purchased power costs, which impact both operating revenues and electric fuel and purchased power expense.

2 Production tax credits, which impact income tax benefit and operating revenues.

3 Commercial includes the impact from data centers.

The electric business reported net income of $14.7 million in the second quarter of 2026, compared to $10.4 million for the same period in 2025. This increase was largely the result of higher retail sales revenue, primarily from recovery mechanisms associated with renewable investments including Badger Wind Farm. Interim rates in Montana and new rates in Wyoming, along with higher retail sales volumes across all major customer classes, further drove the increase. The increase was partially offset by higher interest expense associated with debt issuances for recent capital investments, including Badger Wind Farm, as well as higher depreciation expense and operation and maintenance expense, primarily related to Badger Wind Farm.

Natural Gas Distribution Three Months Ended Six Months Ended

June 30, June 30,

2026 2025 2026 2025

(In millions)

Operating revenues1,2,3

$ 212.6 $ 206.9 $ 675.1 $ 746.2

Operating expenses:

Purchased natural gas sold1

103.4 105.8 377.2 456.3

Operation and maintenance2

60.8 60.5 126.0 124.1

Depreciation and amortization 26.6 26.5 53.0 52.6

Taxes, other than income3

16.8 17.0 43.3 47.6

Total operating expenses

207.6 209.8 599.5 680.6

Operating income (loss) 5.0 (2.9) 75.6 65.6

Other income 3.8 5.1 6.1 8.4

Interest expense 15.9 13.8 32.2 28.6

Income (loss) before income taxes (7.1) (11.6) 49.5 45.4

Income tax (benefit) expense (3.2) (4.2) 9.2 8.1

Net income (loss) $ (3.9) $ (7.4) $ 40.3 $ 37.3

Operating Statistics Three Months Ended Six Months Ended

June 30, June 30,

2026 2025 2026 2025

Revenues (millions)1,2,3

Retail Sales:

Residential $ 111.1 $ 106.1 $ 370.6 $ 397.7

Commercial 63.5 63.4 213.7 253.0

Industrial 8.7 9.4 22.1 25.1

183.3 178.9 606.4 675.8

Transportation and other 29.3 28.0 68.7 70.4

$ 212.6 $ 206.9 $ 675.1 $ 746.2

Volumes (MMdk)

Retail sales:

Residential

9.1 8.5 35.6 40.3

Commercial

7.4 7.0 26.0 28.9

Industrial

1.1 1.0 2.6 2.7

17.6 16.5 64.2 71.9

Transportation sales:

Commercial

.3 .3 .9 1.1

Industrial

32.4 38.1 71.3 86.5

32.7 38.4 72.2 87.6

Total throughput

50.3 54.9 136.4 159.5

Average cost of natural gas per dk

$ 5.88 $ 6.42 $ 5.88 $ 6.35

The previous tables reflect items that are passed through to customers resulting in minimal impact to earnings. These items include:

1 Natural gas costs, which impact operating revenues and purchased natural gas sold.

2 Conservation, which impacts operating revenues and operation and maintenance expense.

3 Revenue-based taxes that impact both operating revenues and taxes, other than income.

The natural gas distribution business reported a seasonal loss of $3.9 million in the second quarter of 2026, compared to a seasonal loss of $7.4 million for the same period in 2025. The lower seasonal loss was primarily driven by new rates in Idaho, Washington, Montana and Wyoming, as well as higher retail sales volumes across all customer classes. These impacts were partially offset by higher interest expense resulting from higher long-term debt balances.

Pipeline

Three Months Ended Six Months Ended

June 30, June 30,

2026 2025 2026 2025

(In millions)

Operating revenues

$ 56.7 $ 56.3 $ 113.8 $ 113.0

Operating expenses:

Operation and maintenance

22.4 22.4 43.2 41.7

Depreciation and amortization 8.3 7.9 16.5 15.9

Taxes, other than income

3.7 3.6 7.5 6.9

Total operating expenses

34.4 33.9 67.2 64.5

Operating income 22.3 22.4 46.6 48.5

Other income .3 1.7 — 2.1

Interest expense 4.2 4.3 8.2 8.5

Income before income taxes 18.4 19.8 38.4 42.1

Income tax expense 4.0 4.4 8.7 9.5

Net income $ 14.4 $ 15.4 $ 29.7 $ 32.6

Operating Statistics Three Months Ended Six Months Ended

June 30, June 30,

2026 2025 2026 2025

Transportation volumes (MMdk)

150.4 151.4 293.6 294.9

Customer natural gas storage balance (MMdk):

Beginning of period

27.3 22.1 37.6 44.1

Net injection (withdrawal) 14.2 12.5 3.9 (9.5)

End of period

41.5 34.6 41.5 34.6

The pipeline business reported net income of $14.4 million in the second quarter of 2026, compared to $15.4 million for the same period in 2025. The decrease was driven by lower other income and higher depreciation and amortization expense from a growth project placed in service. These impacts were partially offset by continued customer demand for short-term natural gas transportation contracts and interruptible storage services, as well as contributions from previously constructed growth projects, including a contracted volume increase.

Other

Three Months Ended Six Months Ended

June 30, June 30,

2026 2025 2026 2025

(In millions)

Operating revenues

$ .2 $ .1 $ .4 $ .3

Operating expenses:

Operation and maintenance

.2 .4 .7 .5

Total operating expenses

.2 .4 .7 .5

Operating loss — (.3) (.3) (.2)

Other income .6 1.6 1.7 3.0

Interest expense .6 .9 2.0 1.9

Income (loss) before income taxes — .4 (.6) .9

Income tax (benefit) expense 5.9 4.7 (1.6) (0.4)

Income (loss) from continuing operations (5.9) (4.3) 1.0 1.3

Discontinued operations, net of tax 2.0 (.4) 1.9 (.9)

Net income (loss) $ (3.9) $ (4.7) $ 2.9 $ .4

For the second quarter of 2026 Other reported a net loss of $3.9 million compared to a net loss of $4.7 million for the same period in 2025. The increase was primarily due to income from discontinued operations associated with a $1.5 million tax benefit related to an election to change the tax method for certain strategic initiative costs. Other also reflects income tax adjustments related to the company's annualized estimated tax rate.

Other includes the activities of the captive insurer which insures various types of risks of the company's subsidiaries. Also included in Other is general and administrative costs and interest expense previously allocated to the company's former businesses that did not meet the criteria for discontinued operations. Discontinued operations includes certain costs associated with legacy business activities.

Other Financial Data

June 30,

2026 2025

(In millions, except per share amounts)

(Unaudited)

Book value per common share $ 13.91 $ 13.37

Market price per common share $ 21.21 $ 16.67

Market value as a percent of book value 152.5 % 124.7 %

Total assets $ 7,712 $ 6,946

Total equity $ 2,927 $ 2,732

Total debt $ 2,577 $ 2,182

Capitalization ratios:

Total equity 53.2 % 55.6 %

Total debt 46.8 % 44.4 %

100.0 % 100.0 %

GRAPHIC — MDU RESOURCES LOGO HEADER

GRAPHIC

Filename: header01.jpg · Sequence: 7

Binary file (24712 bytes)

Download header01.jpg

XML — IDEA: XBRL DOCUMENT

XML

Filename: R1.htm · Sequence: 9

v3.26.1

Cover page

Aug. 06, 2026

Entity Information [Line Items]

Document Type

8-K

Document Period End Date

Aug. 06, 2026

Entity Registrant Name

MDU Resources Group, Inc.

Entity Incorporation, State or Country Code

Entity File Number

1-03480

Entity Tax Identification Number

30-1133956

Entity Address, Address Line One

1200 West Century Avenue

Entity Address, Address Line Two

P.O. Box 5650

Entity Address, City or Town

Bismarck

Entity Address, State or Province

Entity Address, Postal Zip Code

58506

City Area Code

701

Local Phone Number

530-1000

Written Communications

false

Soliciting Material

false

Pre-commencement Tender Offer

false

Pre-commencement Issuer Tender Offer

false

Title of 12(b) Security

Common Stock, par value $1.00 per share

Trading Symbol

MDU

Security Exchange Name

NYSE

Entity Emerging Growth Company

false

Entity Central Index Key

0000067716

Amendment Flag

false

- Definition

Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.

+ References

No definition available.

+ Details

Name:

dei_AmendmentFlag

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Area code of city

+ References

No definition available.

+ Details

Name:

dei_CityAreaCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

For the EDGAR submission types of Form 8-K: the date of the report, the date of the earliest event reported; for the EDGAR submission types of Form N-1A: the filing date; for all other submission types: the end of the reporting or transition period. The format of the date is YYYY-MM-DD.

+ References

No definition available.

+ Details

Name:

dei_DocumentPeriodEndDate

Namespace Prefix:

dei_

Data Type:

xbrli:dateItemType

Balance Type:

Period Type:

duration

- Definition

The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.

+ References

No definition available.

+ Details

Name:

dei_DocumentType

Namespace Prefix:

dei_

Data Type:

dei:submissionTypeItemType

Balance Type:

Period Type:

duration

- Definition

Address Line 1 such as Attn, Building Name, Street Name

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine1

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Address Line 2 such as Street or Suite number

+ References

No definition available.

+ Details

Name:

dei_EntityAddressAddressLine2

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the City or Town

+ References

No definition available.

+ Details

Name:

dei_EntityAddressCityOrTown

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Code for the postal or zip code

+ References

No definition available.

+ Details

Name:

dei_EntityAddressPostalZipCode

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Name of the state or province.

+ References

No definition available.

+ Details

Name:

dei_EntityAddressStateOrProvince

Namespace Prefix:

dei_

Data Type:

dei:stateOrProvinceItemType

Balance Type:

Period Type:

duration

- Definition

A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityCentralIndexKey

Namespace Prefix:

dei_

Data Type:

dei:centralIndexKeyItemType

Balance Type:

Period Type:

duration

- Definition

Indicate if registrant meets the emerging growth company criteria.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityEmergingGrowthCompany

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.

+ References

No definition available.

+ Details

Name:

dei_EntityFileNumber

Namespace Prefix:

dei_

Data Type:

dei:fileNumberItemType

Balance Type:

Period Type:

duration

- Definition

Two-character EDGAR code representing the state or country of incorporation.

+ References

No definition available.

+ Details

Name:

dei_EntityIncorporationStateCountryCode

Namespace Prefix:

dei_

Data Type:

dei:edgarStateCountryItemType

Balance Type:

Period Type:

duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:

dei_EntityInformationLineItems

Namespace Prefix:

dei_

Data Type:

xbrli:stringItemType

Balance Type:

Period Type:

duration

- Definition

The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityRegistrantName

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b-2

+ Details

Name:

dei_EntityTaxIdentificationNumber

Namespace Prefix:

dei_

Data Type:

dei:employerIdItemType

Balance Type:

Period Type:

duration

- Definition

Local phone number for entity.

+ References

No definition available.

+ Details

Name:

dei_LocalPhoneNumber

Namespace Prefix:

dei_

Data Type:

xbrli:normalizedStringItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 13e

-Subsection 4c

+ Details

Name:

dei_PreCommencementIssuerTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14d

-Subsection 2b

+ Details

Name:

dei_PreCommencementTenderOffer

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Title of a 12(b) registered security.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection b

+ Details

Name:

dei_Security12bTitle

Namespace Prefix:

dei_

Data Type:

dei:securityTitleItemType

Balance Type:

Period Type:

duration

- Definition

Name of the Exchange on which a security is registered.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 12

-Subsection d1-1

+ Details

Name:

dei_SecurityExchangeName

Namespace Prefix:

dei_

Data Type:

dei:edgarExchangeCodeItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Exchange Act

-Number 240

-Section 14a

-Subsection 12

+ Details

Name:

dei_SolicitingMaterial

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration

- Definition

Trading symbol of an instrument as listed on an exchange.

+ References

No definition available.

+ Details

Name:

dei_TradingSymbol

Namespace Prefix:

dei_

Data Type:

dei:tradingSymbolItemType

Balance Type:

Period Type:

duration

- Definition

Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Securities Act

-Number 230

-Section 425

+ Details

Name:

dei_WrittenCommunications

Namespace Prefix:

dei_

Data Type:

xbrli:booleanItemType

Balance Type:

Period Type:

duration