BUZZ — Knife River rises on report Starboard urges co to explore sale

* Shares of construction materials and contracting service provider Knife River Corp rise 1.5% to $52.20 in extended trading * Activist investor Starboard has taken a significant stake in Knife River, with plans to push the company to improve its margins or explore a sale, Wall Street Journal reports, citing people familiar with the matter * Starboard wants the company to evaluate strategic alternatives including a potential sale, as it believes its business has a high barrier to entry and could be attractive to potential suitors, as per WSJ * Starboard also wants Knife River to commit to narrowing the gap between its EBITDA margins and those of its peers in the next few years, WSJ reports * Knife River and Starboard did not immediately respond to Reuters' requests for comment. Reuters could not independently verify the report. * As of last close, KNF down 26.9% YTD (Dharna Bafna in Bengaluru) ((dharna.bafna@thomsonreuters.com)