MDU Resources announced on Aug. 4, 2022, its intent to separate its construction materials subsidiary, Knife River Corporation, into an independent, publicly traded company, and today announced its board of directors has approved the separation through a pro rata distribution on May 31 to stockholders of record on May 22 of the outstanding shares of common stock of Knife River Holding Company. Related to the Knife River spinoff, an Investor Day is planned for May 18 at the New York Stock Exchange.