MDU RESOURCES GROUP INC

Please refer to the Company's risk factors that are disclosed in Part I, Item 1A. Risk Factors in the 2025 Annual Report that could be materially harmful to the Company's business, prospects, financial condition or financial results if they occur. At September 30, 2026, there were no material changes to the Company's risk factors provided in Part I, Item 1A. Risk Factors in the 2025 Annual Report other than as set forth below.

The proposed Bakken East pipeline project involves substantial capital investment and is subject to numerous risks and uncertainties that could materially adversely affect the Company’s business, financial condition, results of operations, and cash flows.

On September 30, 2026, the Company’s board of directors approved a final investment decision to proceed with the proposed Bakken East pipeline project through the Company’s pipeline business, WBI Energy Transmission. Bakken East is expected to include approximately 350 miles of pipeline and provide approximately 1.4 billion cubic feet per day of natural gas transportation capacity. Bakken East is expected to be constructed in two phases, targeted for completion in late 2029 and late 2030. The estimated aggregate cost is approximately $2.8 billion to $3.1 billion, none of which amount is currently included in the Company’s capital plan outlined in the 2025 Annual Report. Bakken East is subject to numerous risks and uncertainties, many of which are beyond the Company’s control. These include:

•Project costs and execution. Actual costs and construction timelines could differ materially from current estimates due to inflation, tariffs, changes in materials and labor costs, labor shortages, equipment availability, supply chain disruptions, contractor performance, adverse weather, unforeseen site or environmental conditions, changes in project scope or design, permitting or regulatory requirements, including environmental requirements, and other factors. Cost increases or delays could adversely affect project returns, our financial condition and credit ratings, and our ability to fund other capital projects or pay dividends.

•Financing and partnership arrangements. The Company has not yet secured definitive project financing or one or more project partners. The Company's ability to obtain financing or secure suitable partners on acceptable terms may be affected by capital-market conditions, interest rates, investor interest and other factors. Any partnership arrangement could also require the Company to share economic returns, control, and/or decision-making authority.

•Regulatory approvals. Bakken East requires federal, state, and local regulatory approvals and permits, which may not be received on the anticipated terms or timeline and could result in delays, additional costs or changes to the project.

•Project economics and commercial commitments. Although the Company has entered into precedent agreements representing nearly 1.2 billion cubic feet per day of firm natural gas transportation capacity, the precedent agreements are subject to conditions precedent. The loss of one or more customers, or their failure to fulfill contractual commitments, could adversely affect project revenues and expected financial returns.The Bakken East project economics also depend on continued natural gas production and demand for natural gas transportation capacity in the Bakken region. Changes in commodity prices, competing pipeline capacity, energy policy or customer circumstances could adversely affect utilization and expected financial returns.

•Other project and operating risks. Bakken East may not operate as expected or achieve anticipated financial returns due to operating disruptions, equipment failures, severe weather, cybersecurity incidents, third-party damage or other events. The Company has also incurred, and expects to continue to incur, significant development costs, including engineering, environmental, legal, regulatory, land acquisition and advisory expenses, some of which may not be recoverable if Bakken East is delayed, modified or not completed as currently contemplated.

Any of these risks could cause Bakken East to be delayed, cost more than anticipated, fail to achieve expected financial returns or not be completed as currently contemplated, which could materially adversely affect the Company's business, financial condition, results of operations and cash flows.