by Chris Isidore, CNN Money.

Icahn owns an 82% stake in the firm CVR Energy (CVI), and saw a gain of nearly $160 million on paper the day after the announcement. His CVR investment makes up about 7% of the portfolio of Icahn Associates Holding, one of his his investment firms.

Shares of Icahn's publicly traded hedge fund, Icahn Enterprises (IEP), also jumped on the news. They rose 7.5% and lifted the value of Icahn's own shares in the firm by $569 million. Icahn Enterprises and CVR were each up nearly 1% Friday.

The stock gains are an indicator of the possible conflicts of interest that could occur when a hedge fund manager such as Icahn has a role in advising what regulations should stay and which should go.

Icahn has been leading the debate against Environment Protection Agency regulations that essentially require small, independent refineries like CVR to buy EPA credits that are created when ethanol is blended into gasoline. CVR Energy reported paying $58 million for those credits in the third quarter alone, eating into its profits. Those credits, which are traded on Wall Street, fell about 11% in trading Thursday while CVR's shares climbed, said Tom Kloza, chief oil analyst for the Oil Price Information Service.