MDU RESOURCES GROUP INC

The Company is a pure-play regulated energy delivery business. Its principal executive offices are located at 1200 West Century Avenue, P.O. Box 5650, Bismarck, North Dakota 58506-5650, telephone (701) 530-1000.

Montana-Dakota was incorporated under the state laws of Delaware in 1924. The Company was incorporated under the state laws of Delaware in 2018. Upon the completion of the Holding Company Reorganization, Montana-Dakota became a subsidiary of the Company. The Company adopted a new mission statement in early 2025, "With integrity, deliver value as a leading energy provider and employer of choice."

Through a strategy focusing on its "CORE," the Company strives to deliver superior value and achieve industry-leading performance as a pure-play regulated energy delivery company, while pursuing organic growth opportunities. The Company's "CORE" strategy prioritizes customers and communities, operational excellence, returns focused initiatives and an employee driven culture. The Company generates, transmits and distributes electricity and provides natural gas distribution, transportation and storage services. These businesses are regulated by state public service commissions and/or the FERC.

As part of the Company's continual review of its business, the Company announced strategic initiatives to enhance stockholder value. On May 31, 2023, the Company executed the separation of Knife River, the construction materials and contracting business, from the Company, resulting in Knife River becoming an independent, publicly-traded company. On October 31, 2024, the Company completed the separation of Everus, the construction services business, from the Company, resulting in Everus becoming an independent, publicly-traded company.

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As of December 31, 2025, the Company was organized into three reportable business segments. These business segments include: electric, natural gas distribution and pipeline. The Company's business segments are determined based on the Company's method of internal reporting, which generally segregates the business activities by differences in products and services. The internal reporting of these segments is defined based on the reporting and review process used by the Company's chief executive officer.

The Company, through its wholly-owned subsidiary, MDU Energy Capital, owns Montana-Dakota, Cascade and Intermountain. The electric segment is comprised of Montana-Dakota while the natural gas distribution segment is comprised of Montana-Dakota, Cascade and Intermountain.

The Company, through its wholly-owned subsidiary, Centennial, owns WBI Energy and Centennial Capital. WBI Energy is the pipeline segment and Centennial Capital is reflected in the Other category.

The financial results and data applicable to each of the Company's business segments, as well as their financing requirements, are set forth in Item 7 - MD&A and Item 8 - Note 14.

The Company's material properties, which are of varying ages and are of different construction types, are generally in good condition, are well maintained and are generally suitable and adequate for the purposes for which they are used.

Human Capital Management An employee driven culture is part of the Company's "CORE" strategy, which means striving to be an employer of choice. It begins with employee feedback on continuous improvement and fosters an inclusive and respectful culture. It also includes driving employee safety through proactive safety management systems. As of December 31, 2025, the Company had 2,096 employees.

Many of the Company's employees are represented by collective-bargaining agreements and the Company is committed to establishing constructive dialogue with this representation and bargaining in good faith. The majority of the collective-bargaining agreements contain provisions that prohibit work stoppages or strikes and provide dispute resolution through binding arbitration in the event of an extended disagreement.

The following information about the Company's collective-bargaining agreements is as of December 31, 2025.

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Respectful Workplace The Company is committed to an environment that respects the differences and embraces the strengths of its employees. Essential to the Company's success is its ability to attract, retain and engage the best people from a broad range of backgrounds and build an inclusive culture where all employees feel valued and contribute their best. The Company requires employees to participate in its Leading with Integrity Policy which provides training on the Company's code of conduct.

The Company's goals related to a respectful workplace include:

•Enhance collaboration efforts through cooperation and sharing of best practices to create new ways of meeting employee, customer and stockholder needs.

•Increase productivity and profitability through the creation of a work environment which values all perspectives and methods of accomplishing work.

The Company also promotes recognition of employees through the following awards:

Building People Being employee driven begins with employee recruitment. The Company hires employees that have the skills, abilities and motivation to achieve the results needed for their jobs. Each job is important and part of a coordinated team effort to accomplish the organization's objectives. The Company uses a variety of means to recruit new employees for open positions including posting on the Company's website. Other sources for employee recruitment include employee referrals, union workforce, direct recruitment, advertising, social media, career fairs, partnerships with colleges and technical schools, job service organizations and associations connected with a variety of professions. The Company also uses internship programs to introduce individuals to the Company's business operations and provide a possible source of future employees.

Being employee driven also requires developing employees in their current positions and for future advancement. The Company provides opportunities for advancement through job mobility, succession planning and promotions both within and between business segments. The Company requires employees included in the succession planning process to participate in and further develop their skills for potential advancement in the future. Succession planning is performed across the organization for all levels of leadership. The Company provides employees the opportunity to further develop and grow through various forms of training, mentorship programs and internship programs, among other things.

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To attract and retain employees, the Company offers:

The chief executive officer engages in employee tours at Company locations and the Company conducts employee surveys to hear and gauge employee opinions on issues such as integrity, safety, respect, excellence and stewardship. Survey responses are compiled and evaluated at various levels throughout the Company to develop action plans to address areas of concern raised by employees.

Safety Safety is one of the Company's corporate values. The Company is committed to safety and health in the workplace. To ensure safe work environments, the Company provides training, resources and appropriate follow-up on any unsafe conditions or actions. To facilitate a strong safety culture, the Company established its Safety Leadership Council. In addition to the Safety Leadership Council, the Company has policies and training that support safety in the workplace including training on safety matters through classroom and toolbox meetings on job sites. The Company utilizes safety compliance in the evaluation of employees, which includes management, and recognizes employee safety through safety award programs. Accident and safety statistical information is regularly reported to management and the Board.

Environmental Matters The Company believes it has a responsibility to use natural resources efficiently and attempt to minimize the environmental impact of its activities. The Company produces GHG emissions primarily from its fossil fuel electric-generating facilities, as well as from natural gas pipeline and storage systems, and operations of equipment and fleet vehicles. The Company has developed renewable generation with lower or no GHG emissions. Governmental legislation and regulatory initiatives regarding environmental and energy policy are continuously evolving and could negatively impact the Company's operations and financial results. The Company will continue to monitor legislative and regulatory activity related to environmental and energy policy initiatives and take all appropriate action to comply. In addition, for a discussion of the Company's risks related to environmental laws and regulations, see Item 1A - Risk Factors.

For more information on the Company's environmental, social and governance initiatives and goals, practices and progress, see the Company's Impact Report on its website, which is not incorporated by reference herein.

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Governmental Matters The Company's operations and certain of its subsidiaries are subject to laws and regulations relating to air, water and solid waste pollution control; federal and state facility-siting regulations; zoning and planning regulations of certain state and local authorities; federal and state health and safety regulations; and state hazard communication standards.The Company strives to be in compliance with applicable regulations. For more information, see Environmental matters in Item 8 - Note 17. There are no pending CERCLA actions for any of the Company's material properties. However, the Company is involved in certain claims relating to the Bremerton Gasworks Superfund Site. For more information on the Company's environmental matters, see Item 8 - Note 17 and Item 7 - MD&A - Business Section Financial and Operating Data.

Technology The Company uses technology in substantially all aspects of its business operations and requires uninterrupted operation of information technology systems and network infrastructure. For a discussion of the Company's risks related to cybersecurity, see Item 1A - Risk Factors. For more information on the Company's approach to cybersecurity, see Item 1C - Cybersecurity.

Available Information The Company maintains a corporate website at www.mdu.com. The Company's filings with the SEC, including its annual report on Form 10-K, it's quarterly reports on Form 10-Q and current reports on Form 8-K, and all amendments to those reports are available free of charge through this website as soon as reasonably practicable after they are filed with or furnished to the SEC. The Governance section of the website contains the Company's Corporate Governance Guidelines, committee charters, and the Leading with Integrity Policy for directors, officers, and employees, and is incorporated herein by reference. Copies of these documents may also be obtained free of charge upon written request to the Company's corporate secretary at MDU Resources Group, Inc., P.O. Box 5650, Bismarck, North Dakota 58506. The information available on, or accessible through, the Company's website is not part of this Annual Report on Form 10-K.

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