| ☒ | QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 | ||||
| ☐ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 | ||||
| Delaware | 30-1133956 | |||||||
| (State or other jurisdiction of incorporation or organization) | (I.R.S. Employer Identification No.) | |||||||
| 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 | ||||||
Large Accelerated Filer | ☒ | Accelerated Filer | ☐ | ||||||||
Non-Accelerated Filer | ☐ | Smaller Reporting Company | ☐ | ||||||||
Emerging Growth Company | ☐ | ||||||||||
| Index | |||||
| Page | |||||
Consolidated Statements of Income -- Three and Six Months Ended June 30, 2026 and 2025 | |||||
Consolidated Statements of Comprehensive Income -- Three and Six Months Ended June 30, 2026 and 2025 | |||||
Consolidated Balance Sheets -- June 30, 2026 and 2025, and December 31, 2025 | |||||
Consolidated Statements of Equity -- Six Months Ended June 30, 2026 and 2025 | |||||
Consolidated Statements of Cash Flows -- Six Months Ended June 30, 2026 and 2025 | |||||
8. Equity | |||||
13. Debt | |||||
| Abbreviation or Acronym | |||||
2025 Annual Report | Company's Annual Report on Form 10-K for the year ended December 31, 2025 | ||||
| AFUDC | Allowance for funds used during construction | ||||
| Applied Digital | Applied Digital Corporation | ||||
| ASC | FASB Accounting Standards Codification | ||||
| ASU | FASB Accounting Standards Update | ||||
ATM | At-the-Market | ||||
Badger Wind Farm | 250 MW wind turbine farm near Wishek, North Dakota (49.0 percent ownership) | ||||
Big Stone Station | 475-MW coal-fired electric generating facility near Big Stone City, South Dakota (22.7 percent ownership) | ||||
Binding Open Season | A formal bidding procedure used by pipelines to determine the level of interest of existing and potential shippers for new or additional firm transportation service | ||||
| Cascade | Cascade Natural Gas Corporation, an indirect wholly-owned subsidiary of MDU Energy Capital | ||||
| Centennial | CEHI, LLC, a direct wholly-owned subsidiary of the Company, formerly known as Centennial Energy Holdings, Inc., prior to the separation of Knife River from the Company. References to Centennial's historical business and operations refer to the business and operations of Centennial Energy Holdings, Inc. | ||||
| Centennial Capital | Centennial Holdings Capital LLC, a direct wholly-owned subsidiary of Centennial | ||||
| CODM | Chief Operating Decision Maker | ||||
| Company | MDU Resources Group, Inc. | ||||
| COVID-19 | Coronavirus disease 2019 | ||||
| Coyote Creek | Coyote Creek Mining Company, LLC, a subsidiary of The North American Coal Corporation | ||||
| Coyote Station | 427-MW coal-fired electric generating facility near Beulah, North Dakota (25 percent ownership) | ||||
CPP | Climate Protection Program | ||||
| CWIP | Construction work in progress, costs associated with the construction of new utility facilities recorded on the balance sheet until these facilities are placed in service | ||||
| dk | Decatherm | ||||
EDA | Equity Distribution Agreement | ||||
Eighth Circuit | United States Court of Appeals for the Eighth Circuit | ||||
| EPA | United States Environmental Protection Agency | ||||
| Everus | Everus Construction Group, Inc., a wholly-owned subsidiary of the Company prior to the separation from the Company, that was established in conjunction with the separation of Everus Construction | ||||
| Everus Construction | Everus Construction, Inc., a direct wholly-owned subsidiary of Centennial prior to the separation from the Company, formerly known as MDU Construction Services Group, Inc. prior to March 12, 2024 | ||||
| Exchange Act | Securities Exchange Act of 1934, as amended | ||||
| FASB | Financial Accounting Standards Board | ||||
| FERC | Federal Energy Regulatory Commission | ||||
| FSA | Forward sale agreement | ||||
| GAAP | Accounting principles generally accepted in the United States of America | ||||
| GHG | Greenhouse gas | ||||
| Holding Company Reorganization | The internal holding company reorganization completed on January 1, 2019, pursuant to the agreement and plan of merger, dated as of December 31, 2018, by and among Montana-Dakota, the Company and MDUR Newco Sub, which resulted in the Company becoming a holding company and owning all of the outstanding capital stock of Montana-Dakota | ||||
| HPC | High performance computing | ||||
| Intermountain | Intermountain Gas Company, an indirect wholly-owned subsidiary of MDU Energy Capital | ||||
| JETx | 345-kV transmission line from Jamestown, North Dakota to Ellendale, North Dakota (50 percent ownership) | ||||
| kWh | Kilowatt-hour | ||||
| kV | Kilovolt | ||||
| MDU Energy Capital | MDU Energy Capital, LLC, a direct wholly-owned subsidiary of the Company | ||||
| MDUR Newco | MDUR Newco, Inc., a public holding company created by implementing the Holding Company Reorganization, now known as the Company | ||||
| MDUR Newco Sub | MDUR Newco Sub, Inc., a direct, wholly-owned subsidiary of MDUR Newco, which was merged with and into Montana-Dakota in the Holding Company Reorganization | ||||
| MISO | Midcontinent Independent System Operator, Inc., the organization that provides open-access transmission services and monitors the high-voltage transmission system in the Midwest United States and Manitoba, Canada and a southern United States region which includes much of Arkansas, Mississippi, and Louisiana | ||||
| MMcf | Million cubic feet | ||||
| MMdk | Million dk | ||||
| Montana-Dakota | Montana-Dakota Utilities Co., a direct wholly-owned subsidiary of MDU Energy Capital | ||||
| MW | Megawatt | ||||
| NDDEQ | North Dakota Department of Environmental Quality | ||||
| NDPSC | North Dakota Public Service Commission | ||||
| NERC | North American Electric Reliability Corporation | ||||
Ninth Circuit | United States Court of Appeals for the Ninth Circuit | ||||
NPA | Note Purchase Agreement | ||||
OBBBA | One Big Beautiful Bill Act | ||||
| ODEQ | Oregon Department of Environmental Quality | ||||
OEQC | Oregon Environmental Quality Commission | ||||
| PHMSA | Pipeline and Hazardous Materials Safety Administration | ||||
Precedent Agreement | An agreement between a pipeline company and a potential customer to enter into a firm transportation service agreement once specified events, known as conditions precedent, are met within a defined timeframe | ||||
| RNG | Renewable natural gas | ||||
| SBCC | State Building Code Council | ||||
| SDPUC | South Dakota Public Utilities Commission | ||||
SOFR | Secured Overnight Financing Rate | ||||
| SEC | United States Securities and Exchange Commission | ||||
| TSA | In connection with the separation of Everus, the Company and Everus entered into a Transition Services Agreement whereby each party provided certain post-separation services on a transitional basis | ||||
| VIE | Variable interest entity | ||||
| WBI Energy | WBI Energy, Inc., an indirect wholly-owned subsidiary of Centennial | ||||
| WBI Energy Transmission | WBI Energy Transmission, Inc., an indirect wholly-owned subsidiary of Centennial | ||||
MDU Resources Group, Inc. | ||||||||||||||
| Consolidated Statements of Income | ||||||||||||||
| (Unaudited) | ||||||||||||||
| Three Months Ended | Six Months Ended | |||||||||||||
| June 30, | June 30, | |||||||||||||
| 2026 | 2025 | 2026 | 2025 | |||||||||||
| (In thousands, except per share amounts) | ||||||||||||||
| Operating revenues | $ | 375,303 | $ | 351,186 | $ | 981,280 | $ | 1,026,019 | ||||||
| Operating expenses: | ||||||||||||||
| Purchased natural gas sold | 93,538 | 96,057 | 332,929 | 413,214 | ||||||||||
| Electric fuel and purchased power | 38,674 | 34,891 | 84,741 | 78,639 | ||||||||||
| Operation and maintenance | 114,016 | 112,887 | 228,921 | 223,934 | ||||||||||
| Depreciation and amortization | 55,183 | 51,853 | 109,362 | 103,114 | ||||||||||
| Taxes, other than income | 25,947 | 25,166 | 61,677 | 63,923 | ||||||||||
| Total operating expenses | 327,358 | 320,854 | 817,630 | 882,824 | ||||||||||
| Operating income | 47,945 | 30,332 | 163,650 | 143,195 | ||||||||||
| Other income | 6,227 | 9,945 | 8,832 | 14,942 | ||||||||||
| Interest expense | 31,548 | 25,445 | 64,233 | 52,267 | ||||||||||
| Income before income taxes | 22,624 | 14,832 | 108,249 | 105,870 | ||||||||||
| Income taxes | 3,351 | 655 | 8,029 | 9,226 | ||||||||||
| Income from continuing operations | 19,273 | 14,177 | 100,220 | 96,644 | ||||||||||
| Discontinued operations, net of tax | 1,967 | (397) | 1,837 | (899) | ||||||||||
| Net income | $ | 21,240 | $ | 13,780 | $ | 102,057 | $ | 95,745 | ||||||
| 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 | 209,630 | 204,331 | 207,545 | 204,237 | ||||||||||
| Weighted average common shares outstanding - diluted | 211,663 | 205,211 | 209,342 | 205,086 | ||||||||||
| MDU Resources Group, Inc. | |||||||||||||||||
| Consolidated Statements of Comprehensive Income | |||||||||||||||||
| (Unaudited) | |||||||||||||||||
| Three Months Ended | Six Months Ended | ||||||||||||||||
| June 30, | June 30, | ||||||||||||||||
| 2026 | 2025 | 2026 | 2025 | ||||||||||||||
| (In thousands) | |||||||||||||||||
| Net income | $ | 21,240 | $ | 13,780 | $ | 102,057 | $ | 95,745 | |||||||||
| Other comprehensive income: | |||||||||||||||||
| Postretirement liability adjustment: | |||||||||||||||||
Amortization of postretirement liability losses included in net periodic benefit credit, net of tax of $50 and $33 for the three months ended and $85 and $51 for the six months ended in 2026 and 2025, respectively | 159 | 103 | 333 | 221 | |||||||||||||
Net unrealized (loss) gain on available-for-sale investments: | |||||||||||||||||
Net unrealized (loss) gain on available-for-sale investments arising during the period, net of tax of $(10) and $4 for the three months ended and $(20) and $23 for the six months ended in 2026 and 2025, respectively | (39) | 14 | (76) | 85 | |||||||||||||
Reclassification adjustment for loss on available-for-sale investments included in net income, net of tax of $1 and $1 for the three months ended and $2 and $1 for the six months ended in 2026 and 2025, respectively | 3 | 3 | 6 | 6 | |||||||||||||
| Net unrealized (loss) gain on available-for-sale investments | (36) | 17 | (70) | 91 | |||||||||||||
| Other comprehensive income | 123 | 120 | 263 | 312 | |||||||||||||
| Comprehensive income attributable to common stockholders | $ | 21,363 | $ | 13,900 | $ | 102,320 | $ | 96,057 | |||||||||
| MDU Resources Group, Inc. | |||||||||||
| Consolidated Balance Sheets | |||||||||||
| (Unaudited) | |||||||||||
| June 30, 2026 | June 30, 2025 | December 31, 2025 | |||||||||
| Assets | (In thousands, except shares and per share amounts) | ||||||||||
| Current assets: | |||||||||||
| Cash, cash equivalents and restricted cash | $ | 46,269 | $ | 58,801 | $ | 28,212 | |||||
| Receivables, net | 151,694 | 156,728 | 258,631 | ||||||||
| Current regulatory assets | 192,794 | 141,744 | 179,579 | ||||||||
| Inventories | 19,330 | 19,713 | 39,052 | ||||||||
| Current environmental allowances | 24,242 | 20,449 | 26,194 | ||||||||
| Prepayments and other current assets | 61,646 | 44,491 | 40,768 | ||||||||
| Total current assets | 495,975 | 441,926 | 572,436 | ||||||||
| Noncurrent assets: | |||||||||||
| Property, plant and equipment | 8,408,615 | 7,711,004 | 8,264,972 | ||||||||
| Less accumulated depreciation and amortization | 2,351,592 | 2,276,447 | 2,304,787 | ||||||||
| Net property, plant and equipment | 6,057,023 | 5,434,557 | 5,960,185 | ||||||||
| Goodwill | 345,736 | 345,736 | 345,736 | ||||||||
| Regulatory assets | 295,865 | 309,302 | 297,218 | ||||||||
| Investments | 123,137 | 115,784 | 121,177 | ||||||||
| Environmental allowances | 162,151 | 111,671 | 112,376 | ||||||||
| Other | 232,187 | 186,941 | 213,078 | ||||||||
| Total noncurrent assets | 7,216,099 | 6,503,991 | 7,049,770 | ||||||||
| Total assets | $ | 7,712,074 | $ | 6,945,917 | $ | 7,622,206 | |||||
| Liabilities and Stockholders' Equity | |||||||||||
| Current liabilities: | |||||||||||
| Long-term debt due within one year | $ | 4,700 | $ | 136,700 | $ | 144,700 | |||||
| Accounts payable | 110,742 | 107,178 | 148,970 | ||||||||
| Regulatory liabilities due within one year | 156,951 | 134,254 | 148,584 | ||||||||
| Taxes payable | 34,359 | 53,428 | 44,686 | ||||||||
| Dividends payable | 29,449 | 26,563 | 28,614 | ||||||||
| Accrued compensation | 21,409 | 20,795 | 34,666 | ||||||||
| Current environmental obligations | 24,086 | 19,561 | 24,086 | ||||||||
| Other accrued liabilities | 118,035 | 96,312 | 110,917 | ||||||||
| Total current liabilities | 499,731 | 594,791 | 685,223 | ||||||||
| Noncurrent liabilities: | |||||||||||
| Long-term debt | 2,572,457 | 2,045,235 | 2,532,155 | ||||||||
| Deferred income taxes | 454,147 | 426,556 | 437,286 | ||||||||
| Regulatory liabilities | 478,405 | 468,168 | 472,329 | ||||||||
| Asset retirement obligations | 441,048 | 415,137 | 431,587 | ||||||||
| Environmental obligations | 153,741 | 93,451 | 108,448 | ||||||||
| Other | 185,623 | 170,675 | 182,261 | ||||||||
| Total noncurrent liabilities | 4,285,421 | 3,619,222 | 4,164,066 | ||||||||
| Commitments and contingencies | |||||||||||
Stockholders' equity: | |||||||||||
Common stock Authorized - 500,000,000 shares, $1.00 par value Shares issued - 210,349,456 at June 30, 2026, 204,331,170 at June 30, 2025 and 204,382,821 at December 31, 2025 | 210,349 | 204,331 | 204,383 | ||||||||
| Other paid-in capital | 1,580,599 | 1,472,150 | 1,476,355 | ||||||||
| Retained earnings | 1,152,426 | 1,071,909 | 1,108,894 | ||||||||
| Accumulated other comprehensive loss | (16,452) | (16,486) | (16,715) | ||||||||
| Total stockholders' equity | 2,926,922 | 2,731,904 | 2,772,917 | ||||||||
| Total liabilities and stockholders' equity | $ | 7,712,074 | $ | 6,945,917 | $ | 7,622,206 | |||||
| MDU Resources Group, Inc. | ||||||||||||||||||||
| Consolidated Statements of Equity | ||||||||||||||||||||
| (Unaudited) | ||||||||||||||||||||
| Other Paid-in Capital | Retained Earnings | Accumulated Other Comprehensive Loss | ||||||||||||||||||
| Common Stock | ||||||||||||||||||||
| Shares | Amount | Total | ||||||||||||||||||
| (In thousands, except shares) | ||||||||||||||||||||
At December 31, 2025 | 204,382,821 | $ | 204,383 | $ | 1,476,355 | $ | 1,108,894 | $ | (16,715) | $ | 2,772,917 | |||||||||
| Net income | — | — | — | 80,817 | — | 80,817 | ||||||||||||||
| Other comprehensive income | — | — | — | — | 140 | 140 | ||||||||||||||
| Dividends declared on common stock | — | — | — | (28,868) | — | (28,868) | ||||||||||||||
| Stock-based compensation | — | — | 1,932 | — | — | 1,932 | ||||||||||||||
Issuance of common stock, net | 4,300,000 | 4,300 | 76,859 | — | — | 81,159 | ||||||||||||||
| Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings | 323,203 | 323 | (4,782) | — | — | (4,459) | ||||||||||||||
| At March 31, 2026 | 209,006,024 | $ | 209,006 | $ | 1,550,364 | $ | 1,160,843 | $ | (16,575) | $ | 2,903,638 | |||||||||
| Net income | — | — | — | 21,240 | — | 21,240 | ||||||||||||||
| Other comprehensive income | — | — | — | — | 123 | 123 | ||||||||||||||
| Dividends declared on common stock | — | — | — | (29,657) | — | (29,657) | ||||||||||||||
| Stock-based compensation | — | — | 1,934 | — | — | 1,934 | ||||||||||||||
| Issuance of common stock, net | 1,343,432 | 1,343 | 28,301 | — | — | 29,644 | ||||||||||||||
| At June 30, 2026 | 210,349,456 | $ | 210,349 | $ | 1,580,599 | $ | 1,152,426 | $ | (16,452) | $ | 2,926,922 | |||||||||
| Other Paid-in Capital | Retained Earnings | Accumulated Other Comprehensive Loss | ||||||||||||||||||
| Common Stock | ||||||||||||||||||||
| Shares | Amount | Total | ||||||||||||||||||
| (In thousands, except shares) | ||||||||||||||||||||
At December 31, 2024 | 203,934,578 | $ | 203,935 | $ | 1,473,738 | $ | 1,029,699 | $ | (16,798) | $ | 2,690,574 | |||||||||
| Net income | — | — | — | 81,965 | — | 81,965 | ||||||||||||||
| Other comprehensive income | — | — | — | — | 192 | 192 | ||||||||||||||
| Dividends declared on common stock | — | — | — | (26,765) | — | (26,765) | ||||||||||||||
| Stock-based compensation | — | — | 1,646 | — | — | 1,646 | ||||||||||||||
| Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings | 396,592 | 396 | (4,872) | — | — | (4,476) | ||||||||||||||
| At March 31, 2025 | 204,331,170 | $ | 204,331 | $ | 1,470,512 | $ | 1,084,899 | $ | (16,606) | $ | 2,743,136 | |||||||||
| Net income | — | — | — | 13,780 | — | 13,780 | ||||||||||||||
| Other comprehensive income | — | — | — | — | 120 | 120 | ||||||||||||||
| Dividends declared on common stock | — | — | — | (26,770) | — | (26,770) | ||||||||||||||
| Stock-based compensation | — | — | 1,638 | — | — | 1,638 | ||||||||||||||
| At June 30, 2025 | 204,331,170 | $ | 204,331 | $ | 1,472,150 | $ | 1,071,909 | $ | (16,486) | $ | 2,731,904 | |||||||||
| Standard | Description | Effective date | Impact on financial statements/disclosures | ||||||||
| Recently issued accounting standards not yet adopted | |||||||||||
ASU 2024-03 Disaggregation of Income Statement Expenses | In November 2024, the FASB issued guidance to improve the disclosures about a public business entity's expenses and address requests from investors for more detailed information about the types of expenses (including purchases of inventory, employee compensation, depreciation, amortization, and depletion) in commonly presented expense captions (such as cost of sales, selling, general, and administrative; and research and development). | Effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. | The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2027. | ||||||||
ASU 2025-05 Measurement of Credit Losses for Accounts Receivable and Contract Assets | In July 2025, the FASB issued guidance on applying a practical expedient when estimating expected credit losses on current accounts receivable and/or current contract assets arising from transactions under ASC Topic 606 - Revenue from Contracts with Customers. | Effective for annual reporting periods beginning after December 15, 2025. | The Company is currently evaluating the impact the guidance will have on its results of operations, financial position, cash flows, and disclosures for the year ended December 31, 2026. | ||||||||
ASU 2025-06 Targeted Improvements to the Accounting of Internal-Use Software | In September 2025, the FASB issued guidance on accounting for capitalization of development costs for internal-use software under ASC Subtopic 350-40 and the transition approaches to use. | Effective for annual reporting periods beginning after December 15, 2027. | The Company is currently evaluating the impact the guidance will have on its results of operations, financial position, cash flows, and disclosures for the year ended December 31, 2028. | ||||||||
ASU 2025-10 Accounting for Government Grants Received By Business Entities | In December 2025, the FASB issued guidance on accounting for government grants received by business entities that are related to an asset (purchase, construction, or acquisition of a long-lived asset or inventory) or income (reimbursements to a business entity for operating expenses). | Effective for annual reporting periods beginning after December 15, 2028. | The Company is currently evaluating the impact the guidance will have on its results of operations, financial position, cash flows, and disclosures for the year ended December 31, 2029. | ||||||||
| ASU 2026-02 Environmental Credits and Environmental Credit Obligations | In May 2026, the FASB issued guidance on recognition, measurement, presentation, and disclosure requirements for entities that generate, purchase, or receive environmental credits or have environmental compliance obligations that may be settled with environmental credits. | Effective for annual reporting periods beginning after December 15, 2027. | The Company is currently evaluating the impact the guidance will have on its results of operations, financial position, cash flows, and disclosures for the year ended December 31, 2028. | ||||||||
| Three Months Ended | Six Months Ended | |||||||||||||
| June 30, | June 30, | |||||||||||||
| 2026 | 2025 | 2026 | 2025 | |||||||||||
| (In thousands) | ||||||||||||||
| Operating revenues | $ | 1 | $ | — | $ | 1 | $ | — | ||||||
| Operating expenses | (650) | 429 | (494) | 1,028 | ||||||||||
| Operating (loss) income | 651 | (429) | 495 | (1,028) | ||||||||||
| Other income | — | — | — | — | ||||||||||
| Interest expense | — | — | — | — | ||||||||||
| Income (loss) from discontinued operations before income taxes | 651 | (429) | 496 | (1,028) | ||||||||||
Income tax benefit | (1,316) | (32) | (1,341) | (129) | ||||||||||
| Discontinued operations, net of tax | $ | 1,967 | $ | (397) | $ | 1,837 | $ | (899) | ||||||
| Electric | Natural gas distribution | Pipeline | Total | |||||||||||
| (In thousands) | ||||||||||||||
At December 31, 2025 | $ | 506 | $ | 1,443 | $ | — | $ | 1,949 | ||||||
| Current expected credit loss provision | 952 | 1,670 | — | 2,622 | ||||||||||
| Less write-offs charged against the allowance | 1,066 | 1,098 | — | 2,164 | ||||||||||
| Credit loss recoveries collected | 188 | 272 | — | 460 | ||||||||||
| At March 31, 2026 | $ | 580 | $ | 2,287 | $ | — | $ | 2,867 | ||||||
| Current expected credit loss provision | 269 | 219 | — | 488 | ||||||||||
| Less write-offs charged against the allowance | 368 | 1,013 | — | 1,381 | ||||||||||
| Credit loss recoveries collected | 88 | 167 | — | 255 | ||||||||||
| At June 30, 2026 | $ | 569 | $ | 1,660 | $ | — | $ | 2,229 | ||||||
| Electric | Natural gas distribution | Pipeline | Total | |||||||||||
| (In thousands) | ||||||||||||||
At December 31, 2024 | $ | 473 | $ | 1,366 | $ | — | $ | 1,839 | ||||||
| Current expected credit loss provision | 939 | 2,213 | — | 3,152 | ||||||||||
| Less write-offs charged against the allowance | 1,036 | 1,269 | — | 2,305 | ||||||||||
| Credit loss recoveries collected | 166 | 252 | — | 418 | ||||||||||
| At March 31, 2025 | $ | 542 | $ | 2,562 | $ | — | $ | 3,104 | ||||||
| Current expected credit loss provision | 178 | (151) | — | 27 | ||||||||||
| Less write-offs charged against the allowance | 333 | 1,002 | — | 1,335 | ||||||||||
| Credit loss recoveries collected | 74 | 165 | — | 239 | ||||||||||
| At June 30, 2025 | $ | 461 | $ | 1,574 | $ | — | $ | 2,035 | ||||||
| June 30, 2026 | June 30, 2025 | December 31, 2025 | |||||||||
| (In thousands) | |||||||||||
| Natural gas in storage (current) | $ | 14,413 | $ | 14,937 | $ | 34,333 | |||||
| Fuel stock | 4,917 | 4,776 | 4,719 | ||||||||
| Total | $ | 19,330 | $ | 19,713 | $ | 39,052 | |||||
| Three Months Ended | Six Months Ended | |||||||||||||
| June 30, | June 30, | |||||||||||||
| 2026 | 2025 | 2026 | 2025 | |||||||||||
| (In thousands, except per share amounts) | ||||||||||||||
| Weighted average common shares outstanding - basic | 209,630 | 204,331 | 207,545 | 204,237 | ||||||||||
| Effect of dilutive performance share awards and restricted stock units | 2,033 | 880 | 1,797 | 849 | ||||||||||
| Weighted average common shares outstanding - diluted | 211,663 | 205,211 | 209,342 | 205,086 | ||||||||||
| 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 | ||||||
| Shares excluded from the calculation of diluted earnings per share | — | — | 25 | — | ||||||||||
| Dividends declared per common share | $ | .14 | $ | .13 | $ | .28 | $ | .26 | ||||||
| Three Months Ended | Six Months Ended | |||||||||||||
| June 30, | June 30, | |||||||||||||
| 2026 | 2025 | 2026 | 2025 | |||||||||||
| (In thousands) | ||||||||||||||
| Shares issued | 1,343 | — | 1,343 | — | ||||||||||
| Net proceeds | $ | 29,644 | $ | — | $ | 29,644 | $ | — | ||||||
| Issuance costs | $ | 356 | $ | — | $ | 356 | $ | — | ||||||
| Three Months Ended June 30, 2026 | Electric | Natural gas distribution | Pipeline | Other | Total | ||||||||||||
| (In thousands) | |||||||||||||||||
| Residential utility sales | $ | 35,080 | $ | 106,001 | $ | — | $ | — | $ | 141,081 | |||||||
Commercial utility sales* | 50,479 | 66,432 | — | — | 116,911 | ||||||||||||
| Industrial utility sales | 10,946 | 8,593 | — | — | 19,539 | ||||||||||||
| Other utility sales | 2,083 | — | — | — | 2,083 | ||||||||||||
| Natural gas transportation | — | 16,834 | 47,173 | — | 64,007 | ||||||||||||
| Natural gas storage | — | — | 5,530 | — | 5,530 | ||||||||||||
| Other | 18,600 | 11,371 | 4,061 | 201 | 34,233 | ||||||||||||
| Intersegment eliminations | (124) | (86) | (10,052) | (201) | (10,463) | ||||||||||||
| Revenues from contracts with customers | 117,064 | 209,145 | 46,712 | — | 372,921 | ||||||||||||
| Other revenues | (1,148) | 3,502 | 28 | — | 2,382 | ||||||||||||
| Total external operating revenues | $ | 115,916 | $ | 212,647 | $ | 46,740 | $ | — | $ | 375,303 | |||||||
*Commercial utility sales includes the impact from data centers at the electric segment. | |||||||||||||||||
| 12 months or less | Next 13-24 months | 25 months or more | Total | ||||||||
(In millions) | |||||||||||
| $ | 83.8 | $ | 77.7 | $ | 329.9 | $ | 491.4 | ||||
Estimated Recovery or Refund Period as of June 30, 2026 | * | June 30, 2026 | June 30, 2025 | December 31, 2025 | |||||||||||||
| (In thousands) | |||||||||||||||||
| Regulatory assets: | |||||||||||||||||
| Current: | |||||||||||||||||
| Environmental compliance programs | Up to 1 year | $ | 95,915 | $ | 63,245 | $ | 78,784 | ||||||||||
| Conservation programs | Up to 1 year | 33,426 | 21,541 | 29,148 | |||||||||||||
Decoupling mechanisms | Up to 1 year | 23,272 | 7,974 | 17,091 | |||||||||||||
| Cost recovery mechanisms | Up to 1 year | 18,376 | 6,389 | 13,460 | |||||||||||||
| Natural gas costs recoverable through rate adjustments | Up to 1 year | 11,334 | 36,567 | 22,897 | |||||||||||||
| Electric fuel and purchased power deferral | Up to 1 year | 2,043 | 2,050 | 6,902 | |||||||||||||
| Other | Up to 1 year | 8,428 | 3,978 | 11,297 | |||||||||||||
| 192,794 | 141,744 | 179,579 | |||||||||||||||
| Noncurrent: | |||||||||||||||||
| Pension and postretirement benefits | ** | 135,222 | 142,064 | 135,222 | |||||||||||||
| Cost recovery mechanisms | Up to 23 years | 58,977 | 70,533 | 63,328 | |||||||||||||
| Plant costs/asset retirement obligations | Over plant lives | 48,088 | 46,684 | 48,352 | |||||||||||||
| Manufactured gas plant site remediation | - | 28,042 | 27,212 | 28,411 | |||||||||||||
| Taxes recoverable from customers | Over plant lives | 12,101 | 12,220 | 12,250 | |||||||||||||
| Covid-19 deferred costs | Up to 2 years | 3,590 | 3,886 | 3,761 | |||||||||||||
| Long-term debt refinancing costs | Up to 37 years | 1,500 | 1,718 | 1,799 | |||||||||||||
| Other | Up to 13 years | 8,345 | 4,985 | 4,095 | |||||||||||||
| 295,865 | 309,302 | 297,218 | |||||||||||||||
| Total regulatory assets | $ | 488,659 | $ | 451,046 | $ | 476,797 | |||||||||||
| June 30, 2026 | Cost | Gross Unrealized Gains | Gross Unrealized Losses | Fair Value | ||||||||||
| (In thousands) | ||||||||||||||
| Mortgage-backed securities | $ | 8,638 | $ | 1 | $ | 261 | $ | 8,378 | ||||||
| U.S. Treasury securities | 3,767 | 33 | 5 | 3,795 | ||||||||||
| Total | $ | 12,405 | $ | 34 | $ | 266 | $ | 12,173 | ||||||
| June 30, 2025 | Cost | Gross Unrealized Gains | Gross Unrealized Losses | Fair Value | ||||||||||
| (In thousands) | ||||||||||||||
| Mortgage-backed securities | $ | 8,403 | $ | 24 | $ | 260 | $ | 8,167 | ||||||
| U.S. Treasury securities | 3,416 | 53 | 2 | 3,467 | ||||||||||
| Total | $ | 11,819 | $ | 77 | $ | 262 | $ | 11,634 | ||||||
| December 31, 2025 | Cost | Gross Unrealized Gains | Gross Unrealized Losses | Fair Value | ||||||||||
| (In thousands) | ||||||||||||||
| Mortgage-backed securities | $ | 8,539 | $ | 28 | $ | 204 | $ | 8,363 | ||||||
| U.S. Treasury securities | 3,992 | 33 | — | 4,025 | ||||||||||
| Total | $ | 12,531 | $ | 61 | $ | 204 | $ | 12,388 | ||||||
| Fair Value Measurements at June 30, 2026, Using | ||||||||||||||
| Quoted Prices in Active Markets for Identical Assets (Level 1) | Significant Other Observable Inputs (Level 2) | Significant Unobservable Inputs (Level 3) | Balance at June 30, 2026 | |||||||||||
| (In thousands) | ||||||||||||||
| Assets: | ||||||||||||||
| Money market funds | $ | — | $ | 9,191 | $ | — | $ | 9,191 | ||||||
| Insurance contracts* | — | 70,381 | — | 70,381 | ||||||||||
| Available-for-sale securities: | ||||||||||||||
| Mortgage-backed securities | — | 8,378 | — | 8,378 | ||||||||||
| U.S. Treasury securities | — | 3,795 | — | 3,795 | ||||||||||
| Total assets measured at fair value | $ | — | $ | 91,745 | $ | — | $ | 91,745 | ||||||
*The insurance contracts invest approximately 52 percent in fixed-income investments, 20 percent in common stock of large-cap companies, 11 percent in target date investments, 8 percent in common stock of mid-cap companies, 4 percent in common stock of small-cap companies, 3 percent in cash equivalents, 1 percent in international investments, and 1 percent in real estate. | ||
| Fair Value Measurements at June 30, 2025, Using | ||||||||||||||
| Quoted Prices in Active Markets for Identical Assets (Level 1) | Significant Other Observable Inputs (Level 2) | Significant Unobservable Inputs (Level 3) | Balance at June 30, 2025 | |||||||||||
| (In thousands) | ||||||||||||||
| Assets: | ||||||||||||||
| Money market funds | $ | — | $ | 8,965 | $ | — | $ | 8,965 | ||||||
| Insurance contracts* | — | 64,141 | — | 64,141 | ||||||||||
| Available-for-sale securities: | ||||||||||||||
| Mortgage-backed securities | — | 8,167 | — | 8,167 | ||||||||||
| U.S. Treasury securities | — | 3,467 | — | 3,467 | ||||||||||
| Total assets measured at fair value | $ | — | $ | 84,740 | $ | — | $ | 84,740 | ||||||
*The insurance contracts invest approximately 56 percent in fixed-income investments, 18 percent in common stock of large-cap companies, 10 percent in target date investments, 7 percent in common stock of mid-cap companies, 4 percent in common stock of small-cap companies, 4 percent in cash equivalents, and 1 percent in international investments. | ||
| Fair Value Measurements at December 31, 2025, Using | ||||||||||||||
| Quoted Prices in Active Markets for Identical Assets (Level 1) | Significant Other Observable Inputs (Level 2) | Significant Unobservable Inputs (Level 3) | Balance at December 31, 2025 | |||||||||||
| (In thousands) | ||||||||||||||
| Assets: | ||||||||||||||
| Money market funds | $ | — | $ | 9,839 | $ | — | $ | 9,839 | ||||||
| Insurance contracts* | — | 67,409 | — | 67,409 | ||||||||||
| Available-for-sale securities: | ||||||||||||||
| Mortgage-backed securities | — | 8,363 | — | 8,363 | ||||||||||
| U.S. Treasury securities | — | 4,025 | — | 4,025 | ||||||||||
| Total assets measured at fair value | $ | — | $ | 89,636 | $ | — | $ | 89,636 | ||||||
*The insurance contracts invest approximately 57 percent in fixed-income investments, 18 percent in common stock of large-cap companies, 10 percent in target date investments, 7 percent in common stock of mid-cap companies, 4 percent in common stock of small-cap companies, 3 percent in cash equivalents, and 1 percent in international investments. | ||
| June 30, 2026 | June 30, 2025 | December 31, 2025 | |||||||||
| (In thousands) | |||||||||||
| Carrying amount | $ | 2,577,157 | $ | 2,181,935 | $ | 2,676,855 | |||||
| Fair value | $ | 2,338,445 | $ | 1,886,060 | $ | 2,385,170 | |||||
| Company | Debt-to-Total Capitalization Ratio at June 30, 2026 | Provisions for Increased Borrowings, up to a maximum of: | Facility Limit | Amount Outstanding at June 30, 2026 | Amount Outstanding at June 30, 2025 | Amount Outstanding at December 31, 2025 | Letters of Credit at June 30, 2026 | Expiration Date | ||||||||||||||||||
| (In millions) | ||||||||||||||||||||||||||
| Montana-Dakota Utilities Co. | 51 | % | $ | 250.0 | $ | 200.0 | $ | 82.0 | $ | 43.3 | $ | 132.0 | $ | — | 12/11/30 | |||||||||||
| Cascade Natural Gas Corporation | 49 | % | $ | 225.0 | $ | 175.0 | $ | 108.3 | $ | 14.0 | $ | 96.5 | $ | 2.2 | 12/11/30 | |||||||||||
| Intermountain Gas Company | 53 | % | $ | 225.0 | $ | 175.0 | $ | 77.9 | $ | 86.8 | $ | 67.3 | $ | — | 12/11/30 | |||||||||||
| MDU Resources Group, Inc. | 47 | % | $ | 250.0 | $ | 200.0 | $ | 45.0 | $ | — | $ | 32.9 | $ | 1.0 | 12/11/30 | |||||||||||
Weighted Average Interest Rate at June 30, 2026 | June 30, 2026 | June 30, 2025 | December 31, 2025 | |||||||||||
| (In thousands) | ||||||||||||||
| Senior Notes due on dates ranging from July 15, 2026 to June 15, 2062 | 4.83 | % | $ | 2,110,000 | $ | 1,947,000 | $ | 2,010,000 | ||||||
| Credit agreements due on December 11, 2030 | 5.27 | % | 231,150 | 100,800 | 196,700 | |||||||||
| Term Loan Agreements due on dates ranging from January 31, 2027 to March 31, 2039 | 4.04 | % | 126,900 | 61,600 | 310,900 | |||||||||
| Commercial paper supported by revolving credit agreement | 4.06 | % | 82,000 | 43,300 | 132,000 | |||||||||
| Medium-Term Notes due on dates ranging from September 15, 2027 to March 16, 2029 | 7.32 | % | 35,000 | 35,000 | 35,000 | |||||||||
| Other notes due on November 30, 2038 | 6.00 | % | 321 | 338 | 329 | |||||||||
| Less unamortized debt issuance costs | 8,214 | 6,103 | 8,074 | |||||||||||
| Total long-term debt | 2,577,157 | 2,181,935 | 2,676,855 | |||||||||||
| Less current maturities | 4,700 | 136,700 | 144,700 | |||||||||||
| Net long-term debt | $ | 2,572,457 | $ | 2,045,235 | $ | 2,532,155 | ||||||||
| Three Months Ended June 30, 2026 | Electric | Natural gas distribution | Pipeline | Other | Consolidated | ||||||||||||||||||||||||
| (In thousands) | |||||||||||||||||||||||||||||
| Operating revenues: | |||||||||||||||||||||||||||||
| External operating revenues | $ | 115,916 | $ | 212,647 | $ | 46,740 | $ | — | $ | 375,303 | |||||||||||||||||||
| Intersegment operating revenues | 124 | 86 | 10,052 | 201 | 10,463 | ||||||||||||||||||||||||
| Purchased natural gas sold: | |||||||||||||||||||||||||||||
| External purchased natural gas sold | — | 93,538 | — | — | 93,538 | ||||||||||||||||||||||||
| Intersegment purchased natural gas sold | — | 9,900 | — | — | 9,900 | ||||||||||||||||||||||||
| Electric fuel and purchased power | 38,674 | — | — | — | 38,674 | ||||||||||||||||||||||||
| Operation and maintenance: | |||||||||||||||||||||||||||||
| External operation and maintenance | 31,015 | 60,741 | 22,247 | 13 | 114,016 | ||||||||||||||||||||||||
| Intersegment operation and maintenance | 124 | 86 | 152 | 201 | 563 | ||||||||||||||||||||||||
| Depreciation and amortization | 20,287 | 26,639 | 8,257 | — | 55,183 | ||||||||||||||||||||||||
| Taxes, other than income | 5,368 | 16,806 | 3,773 | — | 25,947 | ||||||||||||||||||||||||
| Other income: | |||||||||||||||||||||||||||||
| External other income | 1,842 | 3,865 | 242 | 278 | 6,227 | ||||||||||||||||||||||||
| Intersegment other income | — | — | 76 | 326 | 402 | ||||||||||||||||||||||||
| Interest expense: | |||||||||||||||||||||||||||||
| External interest expense | 11,094 | 15,945 | 3,801 | 708 | 31,548 | ||||||||||||||||||||||||
| Intersegment interest expense | — | — | 402 | — | 402 | ||||||||||||||||||||||||
| Income tax expense (benefit) | (3,343) | (3,215) | 4,042 | 5,867 | 3,351 | ||||||||||||||||||||||||
| Income (loss) from continuing operations | 14,663 | (3,842) | 14,436 | (5,984) | 19,273 | ||||||||||||||||||||||||
| Discontinued operations, net of tax | — | — | — | 1,967 | 1,967 | ||||||||||||||||||||||||
Net income (loss) | $ | 14,663 | $ | (3,842) | $ | 14,436 | $ | (4,017) | $ | 21,240 | |||||||||||||||||||
| Three Months Ended June 30, 2025 | Electric | Natural gas distribution | Pipeline | Other | Consolidated | ||||||||||||||||||||||||
| (In thousands) | |||||||||||||||||||||||||||||
| Operating revenues: | |||||||||||||||||||||||||||||
| External operating revenues | $ | 97,886 | $ | 206,794 | $ | 46,507 | $ | (1) | $ | 351,186 | |||||||||||||||||||
| Intersegment operating revenues | 140 | 92 | 9,796 | 180 | 10,208 | ||||||||||||||||||||||||
| Purchased natural gas sold: | |||||||||||||||||||||||||||||
| External purchased natural gas sold | — | 96,057 | — | — | 96,057 | ||||||||||||||||||||||||
| Intersegment purchased natural gas sold | — | 9,751 | — | — | 9,751 | ||||||||||||||||||||||||
| Electric fuel and purchased power | 34,891 | — | — | — | 34,891 | ||||||||||||||||||||||||
| Operation and maintenance: | |||||||||||||||||||||||||||||
| External operation and maintenance | 29,823 | 60,456 | 22,352 | 256 | 112,887 | ||||||||||||||||||||||||
| Intersegment operation and maintenance | 140 | 92 | 45 | 180 | 457 | ||||||||||||||||||||||||
| Depreciation and amortization | 17,393 | 26,471 | 7,989 | — | 51,853 | ||||||||||||||||||||||||
| Taxes, other than income | 4,648 | 16,935 | 3,583 | — | 25,166 | ||||||||||||||||||||||||
| Other income: | |||||||||||||||||||||||||||||
| External other income | 2,726 | 5,095 | 1,616 | 508 | 9,945 | ||||||||||||||||||||||||
| Intersegment other income | — | — | 90 | 1,061 | 1,151 | ||||||||||||||||||||||||
| Interest expense: | |||||||||||||||||||||||||||||
| External interest expense | 7,614 | 13,745 | 3,135 | 951 | 25,445 | ||||||||||||||||||||||||
| Intersegment interest expense | — | — | 1,151 | — | 1,151 | ||||||||||||||||||||||||
| Income tax expense (benefit) | (4,254) | (4,170) | 4,337 | 4,742 | 655 | ||||||||||||||||||||||||
Income (loss) from continuing operations | 10,497 | (7,356) | 15,417 | (4,381) | 14,177 | ||||||||||||||||||||||||
| Discontinued operations, net of tax | — | — | — | (397) | (397) | ||||||||||||||||||||||||
Net income (loss) | $ | 10,497 | $ | (7,356) | $ | 15,417 | $ | (4,778) | $ | 13,780 | |||||||||||||||||||
| Six Months Ended June 30, 2026 | Electric | Natural gas distribution | Pipeline | Other | Consolidated | ||||||||||||||||||||||||
| (In thousands) | |||||||||||||||||||||||||||||
| Operating revenues: | |||||||||||||||||||||||||||||
| External operating revenues | $ | 236,934 | $ | 674,994 | $ | 69,352 | $ | — | $ | 981,280 | |||||||||||||||||||
| Intersegment operating revenues | 291 | 175 | 44,512 | 400 | 45,378 | ||||||||||||||||||||||||
| Purchased natural gas sold: | |||||||||||||||||||||||||||||
| External purchased natural gas sold | — | 332,929 | — | — | 332,929 | ||||||||||||||||||||||||
| Intersegment purchased natural gas sold | — | 44,320 | — | — | 44,320 | ||||||||||||||||||||||||
| Electric fuel and purchased power | 84,741 | — | — | — | 84,741 | ||||||||||||||||||||||||
| Operation and maintenance: | |||||||||||||||||||||||||||||
| External operation and maintenance | 59,720 | 125,867 | 43,016 | 318 | 228,921 | ||||||||||||||||||||||||
| Intersegment operation and maintenance | 291 | 175 | 192 | 400 | 1,058 | ||||||||||||||||||||||||
| Depreciation and amortization | 39,914 | 52,972 | 16,476 | — | 109,362 | ||||||||||||||||||||||||
| Taxes, other than income | 10,888 | 43,258 | 7,531 | — | 61,677 | ||||||||||||||||||||||||
| Other income: | |||||||||||||||||||||||||||||
| External other income | 2,293 | 6,135 | (181) | 585 | 8,832 | ||||||||||||||||||||||||
| Intersegment other income | — | — | 191 | 1,131 | 1,322 | ||||||||||||||||||||||||
| Interest expense: | |||||||||||||||||||||||||||||
| External interest expense | 23,005 | 32,231 | 6,903 | 2,094 | 64,233 | ||||||||||||||||||||||||
| Intersegment interest expense | — | — | 1,322 | — | 1,322 | ||||||||||||||||||||||||
Income tax (benefit) expense | (8,255) | 9,211 | 8,744 | (1,671) | 8,029 | ||||||||||||||||||||||||
| Income from continuing operations | 29,214 | 40,341 | 29,690 | 975 | 100,220 | ||||||||||||||||||||||||
| Discontinued operations, net of tax | — | — | — | 1,837 | 1,837 | ||||||||||||||||||||||||
| Net income | $ | 29,214 | $ | 40,341 | $ | 29,690 | $ | 2,812 | $ | 102,057 | |||||||||||||||||||
| Six Months Ended June 30, 2025 | Electric | Natural gas distribution | Pipeline | Other | Consolidated | ||||||||||||||||||||||||
| (In thousands) | |||||||||||||||||||||||||||||
| Operating revenues: | |||||||||||||||||||||||||||||
| External operating revenues | $ | 210,147 | $ | 746,041 | $ | 69,831 | $ | — | $ | 1,026,019 | |||||||||||||||||||
| Intersegment operating revenues | 318 | 187 | 43,132 | 358 | 43,995 | ||||||||||||||||||||||||
| Purchased natural gas sold: | |||||||||||||||||||||||||||||
| External purchased natural gas sold | — | 413,214 | — | — | 413,214 | ||||||||||||||||||||||||
| Intersegment purchased natural gas sold | — | 43,074 | — | — | 43,074 | ||||||||||||||||||||||||
| Electric fuel and purchased power | 78,639 | — | — | — | 78,639 | ||||||||||||||||||||||||
| Operation and maintenance: | |||||||||||||||||||||||||||||
| External operation and maintenance | 58,230 | 123,939 | 41,592 | 173 | 223,934 | ||||||||||||||||||||||||
| Intersegment operation and maintenance | 318 | 187 | 58 | 358 | 921 | ||||||||||||||||||||||||
| Depreciation and amortization | 34,576 | 52,593 | 15,945 | — | 103,114 | ||||||||||||||||||||||||
| Taxes, other than income | 9,463 | 47,563 | 6,897 | — | 63,923 | ||||||||||||||||||||||||
| Other income: | |||||||||||||||||||||||||||||
| External other income | 3,718 | 8,396 | 1,923 | 905 | 14,942 | ||||||||||||||||||||||||
| Intersegment other income | — | — | 213 | 2,047 | 2,260 | ||||||||||||||||||||||||
| Interest expense: | |||||||||||||||||||||||||||||
| External interest expense | 15,501 | 28,621 | 6,256 | 1,889 | 52,267 | ||||||||||||||||||||||||
| Intersegment interest expense | — | — | 2,260 | — | 2,260 | ||||||||||||||||||||||||
Income tax (benefit) expense | (7,985) | 8,131 | 9,464 | (384) | 9,226 | ||||||||||||||||||||||||
| Income from continuing operations | 25,441 | 37,302 | 32,627 | 1,274 | 96,644 | ||||||||||||||||||||||||
| Discontinued operations, net of tax | — | — | — | (899) | (899) | ||||||||||||||||||||||||
| Net income | $ | 25,441 | $ | 37,302 | $ | 32,627 | $ | 375 | $ | 95,745 | |||||||||||||||||||
| Three Months Ended | Six Months Ended | |||||||||||||
| June 30, | June 30, | |||||||||||||
| 2026 | 2025 | 2026 | 2025 | |||||||||||
| (In thousands) | ||||||||||||||
| Operating revenues reconciliation: | ||||||||||||||
| Total reportable segment operating revenues | $ | 385,565 | $ | 361,215 | $ | 1,026,258 | $ | 1,069,656 | ||||||
| Other revenue | 201 | 179 | 400 | 358 | ||||||||||
| Elimination of intersegment operating revenues | (10,463) | (10,208) | (45,378) | (43,995) | ||||||||||
| Total consolidated operating revenues | $ | 375,303 | $ | 351,186 | $ | 981,280 | $ | 1,026,019 | ||||||
| Three Months Ended | Six Months Ended | |||||||||||||
| June 30, | June 30, | |||||||||||||
| 2026 | 2025 | 2026 | 2025 | |||||||||||
| (In thousands) | ||||||||||||||
| Components of net periodic benefit cost: | ||||||||||||||
| Interest cost | $ | 3,128 | $ | 3,303 | $ | 6,256 | $ | 6,606 | ||||||
| Expected return on assets | (3,392) | (3,645) | (6,783) | (7,290) | ||||||||||
| Amortization of net actuarial loss | 1,432 | 1,194 | 2,864 | 2,387 | ||||||||||
| Net periodic benefit cost | $ | 1,168 | $ | 852 | $ | 2,337 | $ | 1,703 | ||||||
| Three Months Ended | Six Months Ended | |||||||||||||
| June 30, | June 30, | |||||||||||||
| 2026 | 2025 | 2026 | 2025 | |||||||||||
| (In thousands) | ||||||||||||||
| Components of net periodic benefit credit: | ||||||||||||||
| Service cost | $ | 94 | $ | 99 | $ | 188 | $ | 198 | ||||||
| Interest cost | 441 | 462 | 882 | 924 | ||||||||||
| Expected return on assets | (1,270) | (1,292) | (2,540) | (2,584) | ||||||||||
| Amortization of prior service credit | (45) | (289) | (90) | (579) | ||||||||||
| Amortization of net actuarial gain | (23) | (80) | (46) | (160) | ||||||||||
| Net periodic benefit credit, including amount capitalized | (803) | (1,100) | (1,606) | (2,201) | ||||||||||
| Less amount capitalized | 17 | 18 | 35 | 36 | ||||||||||
| Net periodic benefit credit | $ | (820) | $ | (1,118) | $ | (1,641) | $ | (2,237) | ||||||
| Three Months Ended | Six Months Ended | ||||||||||||||||
| June 30, | June 30, | ||||||||||||||||
| 2026 | 2025 | 2026 | 2025 | ||||||||||||||
| (In millions, except per share amounts) | |||||||||||||||||
| Electric | $ | 14.7 | $ | 10.4 | $ | 29.2 | $ | 25.4 | |||||||||
| Natural gas distribution | (3.9) | (7.4) | 40.3 | 37.3 | |||||||||||||
| Pipeline | 14.4 | 15.4 | 29.7 | 32.6 | |||||||||||||
| Other | (5.9) | (4.3) | 1.0 | 1.3 | |||||||||||||
| 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 | |||||||||
| Three Months Ended | Six Months Ended | ||||||||||||||||
| June 30, | June 30, | ||||||||||||||||
| 2026 | 2025 | 2026 | 2025 | ||||||||||||||
| (In millions) | |||||||||||||||||
| Operating revenues | $ | 116.1 | $ | 98.1 | $ | 237.3 | $ | 210.5 | |||||||||
| Operating expenses: | |||||||||||||||||
| Electric fuel and purchased power | 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 benefit | (3.4) | (4.1) | (8.3) | (7.9) | |||||||||||||
| Net income | $ | 14.7 | $ | 10.4 | $ | 29.2 | $ | 25.4 | |||||||||
| Three Months Ended | Six Months Ended | ||||||||||||||||
| June 30, | June 30, | ||||||||||||||||
| 2026 | 2025 | 2026 | 2025 | ||||||||||||||
| (In millions) | |||||||||||||||||
| Operating revenues | $ | 212.6 | $ | 206.9 | $ | 675.1 | $ | 746.2 | |||||||||
| Operating expenses: | |||||||||||||||||
| Purchased natural gas sold | 103.4 | 105.8 | 377.2 | 456.3 | |||||||||||||
| Operation and maintenance | 60.8 | 60.5 | 126.0 | 124.1 | |||||||||||||
| Depreciation and amortization | 26.6 | 26.5 | 53.0 | 52.6 | |||||||||||||
| Taxes, other than income | 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 | |||||||||
| 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 | |||||||||||||
| 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) | (.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 | |||||||||
| Three Months Ended | Six Months Ended | ||||||||||||||||
| June 30, | June 30, | ||||||||||||||||
| 2026 | 2025 | 2026 | 2025 | ||||||||||||||
| (In millions) | |||||||||||||||||
| Intersegment transactions: | |||||||||||||||||
| Operating revenues | $ | 10.4 | $ | 10.2 | $ | 45.4 | $ | 44.0 | |||||||||
| Purchased natural gas sold | $ | 9.9 | $ | 9.8 | $ | 44.3 | $ | 43.1 | |||||||||
| Operation and maintenance | $ | .5 | $ | .4 | $ | 1.1 | $ | .9 | |||||||||
| Other income | $ | .4 | $ | 1.2 | $ | 1.3 | $ | 2.3 | |||||||||
| Interest expense | $ | .4 | $ | 1.2 | $ | 1.3 | $ | 2.3 | |||||||||
| Six Months Ended | ||||||||
| June 30, | ||||||||
| 2026 | 2025 | |||||||
| (In millions) | ||||||||
| Net cash provided by (used in): | ||||||||
| Operating activities | $ | 265.3 | $ | 334.9 | ||||
| Investing activities | (196.1) | (174.4) | ||||||
| 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 | ||||
| Six Months Ended | |||||||||||
| June 30, | |||||||||||
| 2026 | 2025 | Variance | |||||||||
| (In millions) | |||||||||||
| Components of net cash provided by operating activities: | |||||||||||
| Net income | $ | 102.1 | $ | 95.7 | $ | 6.4 | |||||
Loss from discontinued operations, net of tax | 1.9 | (0.9) | 2.8 | ||||||||
| Income from continuing operations | 100.2 | 96.6 | 3.6 | ||||||||
| Adjustments to reconcile net income to net cash provided by operating activities: | |||||||||||
| Depreciation, depletion and amortization | 109.4 | 103.1 | 6.3 | ||||||||
| Deferred income taxes | 11.6 | (19.0) | 30.6 | ||||||||
| Other adjustments | 4.5 | 4.0 | .5 | ||||||||
| Changes in current assets and liabilities, net of acquisitions: | |||||||||||
| Receivables | 103.8 | 129.5 | (25.7) | ||||||||
| Inventories | 19.3 | 25.0 | (5.7) | ||||||||
| Other current assets | (23.0) | 86.7 | (109.7) | ||||||||
| Accounts payable | (36.4) | (47.6) | 11.2 | ||||||||
| Other current liabilities | (7.6) | (28.4) | 20.8 | ||||||||
| Pension & postretirement benefit plan contributions | (1.0) | (2.5) | 1.5 | ||||||||
| Other noncurrent changes | (16.8) | (11.8) | (5.0) | ||||||||
| Net cash provided by continuing operations | 264.0 | 335.6 | (71.6) | ||||||||
| Net cash provided by (used in) discontinued operations | 1.3 | (.7) | 2.0 | ||||||||
| Net cash provided by operating activities | $ | 265.3 | $ | 334.9 | $ | (69.6) | |||||
| Six Months Ended | |||||||||||
| June 30, | |||||||||||
| 2026 | 2025 | Variance | |||||||||
| (In millions) | |||||||||||
| Components of net cash used in investing activities: | |||||||||||
| Capital expenditures | $ | (193.5) | $ | (174.0) | $ | (19.5) | |||||
| Cost of removal, net of salvage value | (3.9) | (2.5) | (1.4) | ||||||||
| Purchase of investment securities | (2.7) | (2.9) | .2 | ||||||||
Proceeds from investment securities | 4.0 | 5.0 | (1.0) | ||||||||
| Net cash used in investing activities | $ | (196.1) | $ | (174.4) | $ | (21.7) | |||||
| Six Months Ended | |||||||||||
| June 30, | |||||||||||
| 2026 | 2025 | Variance | |||||||||
| (In millions) | |||||||||||
| Components of net cash used in financing activities: | |||||||||||
| Issuance of long-term debt | $ | 134.5 | $ | — | $ | 134.5 | |||||
| Repayment of long-term debt | (234.0) | (111.0) | (123.0) | ||||||||
| Debt issuance costs | (.6) | — | (.6) | ||||||||
Issuance of common stock, net | 110.8 | — | 110.8 | ||||||||
| Dividends paid | (57.3) | (53.1) | (4.2) | ||||||||
| Tax withholding on stock-based compensation | (4.5) | (4.5) | — | ||||||||
| Net cash used in financing activities | $ | (51.1) | $ | (168.6) | $ | 117.5 | |||||
ISSUER PURCHASES OF EQUITY SECURITIES | ||||||||||||||
| Period | Total Number of Shares (or Units) Purchased (1) | Average Price Paid per Share (or Unit) | Total Number of Shares (or Units) Purchased as Part of Publicly Announced Plans or Programs (2) | Maximum Number (or Approximate Dollar Value) of Shares (or Units) that May Yet Be Purchased Under the Plans or Programs (2) | ||||||||||
| April 1 through April 30, 2026 | — | $ | — | — | — | |||||||||
| May 1 through May 31, 2026 | — | — | — | — | ||||||||||
| June 1 through June 30, 2026 | 1,445 | 21.27 | — | — | ||||||||||
| Total | 1,445 | $ | 21.27 | — | — | |||||||||
(1) Represents shares of common stock purchased on the open market for the Company's non-employee directors who elected to receive additional shares of common stock in lieu of a portion of their cash retainer. (2) Not applicable. The Company does not currently have in place any publicly announced plans or programs to repurchase equity securities. | ||
| Exhibits Index | |||||||||||||||||||||||
| Incorporated by Reference | |||||||||||||||||||||||
| Exhibit Number | Exhibit Description | Filed Herewith | Form | Period Ended | Exhibit | Filing Date | File Number | ||||||||||||||||
| 3(a) | 8-K | 3.2 | 5/8/19 | 1-03480 | |||||||||||||||||||
| 3(b) | 8-K | 3.1 | 2/14/25 | 1-03480 | |||||||||||||||||||
| +10(a) | 8-K | 10.1 | 5/13/26 | 1-03480 | |||||||||||||||||||
| 31(a) | X | ||||||||||||||||||||||
| 31(b) | X | ||||||||||||||||||||||
*32 | X | ||||||||||||||||||||||
| 101.INS | XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document | ||||||||||||||||||||||
| 101.SCH | XBRL Taxonomy Extension Schema Document | ||||||||||||||||||||||
| 101.CAL | XBRL Taxonomy Extension Calculation Linkbase Document | ||||||||||||||||||||||
| 101.DEF | XBRL Taxonomy Extension Definition Linkbase Document | ||||||||||||||||||||||
| 101.LAB | XBRL Taxonomy Extension Label Linkbase Document | ||||||||||||||||||||||
| 101.PRE | XBRL Taxonomy Extension Presentation Linkbase Document | ||||||||||||||||||||||
| 104 | Cover Page Interactive Data File (formatted as Inline XBRL and contained in Exhibit 101) | ||||||||||||||||||||||
+Management contract, compensatory plan, or arrangement. | ||
*Furnished Herewith | ||
| MDU RESOURCES GROUP, INC. | |||||||||||
| DATE: | August 6, 2026 | BY: | /s/ Jason L. Vollmer | ||||||||
| Jason L. Vollmer | |||||||||||
| Chief Financial Officer | |||||||||||
| BY: | /s/ Stephanie A. Sievert | ||||||||||
| Stephanie A. Sievert | |||||||||||
| Chief Accounting and Regulatory Affairs Officer | |||||||||||