Knife River Corporation (NYSE: KNF) issued a statement saying it first learned of an investment by activist firm Starboard Value LP on September 22, 2026, after receiving a letter from the firm.

The construction materials company said its board and management team are open to dialogue with shareholders and plan to engage with Starboard to understand its views. The company did not disclose the size of Starboard's stake or the specific demands made in the letter.

Knife River, which became an independent public company in 2023, said its board regularly reviews opportunities to create shareholder value. The company cited its EDGE initiatives, which it described as focused on pricing optimization, operational performance and margin improvement.

Knife River operates a vertically integrated platform that includes aggregates, ready-mix concrete, asphalt, liquid asphalt and contracting services. The company is a member of the S&P MidCap 400 index.