Material Agreement (Form 8-K)

On August 7, 2025, MDU Resources Group, Inc. (the "Company") entered into a distribution agreement (the "Distribution Agreement") with Wells Fargo Securities, LLC ("Wells Fargo") and BofA Securities, Inc. ("BofA Securities" and, together with Wells Fargo, the "Agents" and "Forward Sellers"), and Bank of America, N.A. and Wells Fargo Bank, National Association (collectively, the "Forward Purchasers") relating to the issuance, offer, and sale from time to time of shares of the Company's common stock, par value $1.00 per share (the "Common Stock"), having an aggregate gross sale price of up to $400 million (including shares of Common Stock that may be sold pursuant to the forward sale agreements described below, the "Shares"). The Shares may be offered and sold by any method or payment permitted by law to be an "at the market offering" as defined in Rule 415 under the Securities Act of 1933, as amended (the "Securities Act"), including by means of ordinary brokers' transactions on the New York Stock Exchange, the existing trading market for the Common Stock, or otherwise at market prices prevailing at the time of sale, or sales made to or through a market maker or through an electronic communications network. In addition, the Shares may be offered and sold by such other methods, including privately-negotiated transactions (including block trades), as the Company and any Agent agree in writing. The Shares may be offered and sold in amounts and at times to be determined by the Company from time to time, but the Company has no obligation to offer and sell any of the Shares. Actual sales will depend on a variety of factors to be determined by the Company from time to time, including (among others) market conditions, the trading price of the Common Stock, and determinations by the Company of the appropriate sources of funding for the Company.

The Distribution Agreement provides that, in addition to the issuance and sale of the Shares by the Company through the Agents in their capacity as Agents, the Company may enter into forward sale agreements with the Forward Purchasers. Concurrently with, and pursuant to, the Distribution Agreement, the Company entered into two separate master forward sale confirmations (the "Master Forward Sale Confirmations"), each dated August 7, 2025, with each of the Forward Purchasers, respectively. In connection with each forward sale agreement under a Master Forward Sale Confirmation, the relevant Forward Purchaser will, at the Company's request, attempt to borrow from third parties and, through the relevant Forward Seller, sell a number of Shares equal to the number of Shares underlying the particular forward sale agreement to hedge the forward sale agreement.

The forward sale price per share under each forward sale agreement will initially equal the product of (1) an amount equal to one minus the applicable forward selling commission, and (2) the volume-weighted average price per share at which the borrowed shares of Common Stock were sold pursuant to the Distribution Agreement by the relevant Forward Seller. Thereafter, the forward sale price will be subject to adjustment as described in the relevant forward sale agreement. The forward sale agreements provide that the forward sale price, as well as the sales prices used to calculate the initial forward sale price, will be subject to increase or decrease based on an interest rate factor equal to the specified benchmark's daily rate less a spread and subject to decrease by amounts related to expected dividends on the Common Stock during the term of the particular forward sale agreement. If the specified benchmark's daily rate is less than the spread for a particular forward sale agreement on any day, the interest factor will result in a reduction of the applicable forward sale price for such day.

The Company will not initially receive any proceeds from the sale of borrowed Shares of the Company's Common Stock by a Forward Seller. If the Company elects to physically settle any forward sale agreement by issuing and delivering shares of Common Stock, the Company will receive an amount of cash from the relevant Forward Purchaser equal to the product of the forward sale price per share under that particular forward sale agreement and the number of shares of Common Stock underlying the particular forward sale agreement. The Company expects to receive proceeds from the sale of Shares by a Forward Seller upon future physical settlement of the relevant forward sale agreement with the relevant Forward Purchaser on dates specified by the Company on or prior to the maturity date of the relevant forward sale agreement. Although the Company expects to settle any forward sale agreement with a full physical settlement, it may, except in limited circumstances, elect a cash or net share settlement for all or a portion of its obligations under such forward sale agreement. If the Company elects to cash settle or net share settle a forward sale agreement, the Company may not (in the case of cash settlement) or will not (in the case of net share settlement) receive any proceeds, and the Company may owe cash (in the case of cash settlement) or shares of Common Stock (in the case of net share settlement) to the relevant Forward Purchaser.

The Company will pay each Agent a commission of up to 1.0% of the sales price of all Shares issued by the Company and sold through it as the Company's Agent under the Distribution Agreement. The commission the Company pays to Agents for sales by privately negotiated transactions (including block trades) or other methods may vary, as the Company and any Agent agree to in writing. The remaining sales proceeds, after deducting any expenses payable by the Company and any transaction fees imposed by any governmental, regulatory, or self-regulatory organization in connection with the sales, will be the Company's net proceeds for the sale of the Shares. In connection with each forward sale agreement, the relevant Forward Seller will receive, reflected in a reduced initial forward sale price payable by the relevant Forward Purchaser under its forward