Activist investor Carl Icahn has taken a small stake in Occidental Petroleum, people close to the matter told CNBC on Friday.
The company is in the middle of a rare bidding war for Anadarko Petroleum, having bid $38 billion for its smaller rival. Chevron had previously bid $33 billion for Anadarko.
Shares of Occidental jumped 2% in extended trading Friday, immediately following the news.
The size of Icahn's stake is still unclear, and Bloomberg — which first reported the stake — reports Icahn hasn't decided whether to push for changes at the company. Still, the stake throws another heavyweight name behind a bidding war that's already captured Wall Street's attention.
Billionaire investor Warren Buffett invested $10 billion in Houston-based Occidental in an effort to help the takeover bid. CNBC reported earlier Friday that Buffett was willing to invest as much as $20 billion.