The company's Dividend Reinvestment and Direct Stock Purchase plan provides interested investors the opportunity to purchase shares of the company's common stock and to reinvest all or a percentage of their dividends without incurring brokerage commissions or service charges.

To obtain a copy of the prospectus:

• Call toll-free at 1-877-536-3553
• Visit www.wellsfargo.com/shareownerservices
• Write to MDU Resources Group, Inc., c/o Wells Fargo Shareowner Services, P.O. Box 64856, St. Paul, MN, 55164-0856

MDU Resources Group, Inc. provides energy, value-added natural resource products and related services that are essential to our country's energy and transportation infrastructure.

This announcement is neither an offer to sell nor a solicitation of an offer to buy any of these securities. The offer is made only by the prospectus.