Icahn, formerly a special advisor to Trump on regulations, had sought changes to the Renewable Fuel Standard, a program that requires fuel refiners to blend renewable biofuels like corn-based ethanol into gasoline and diesel. Those changes would have benefited CVR Energy, in which Icahn Associates holds an 82 percent stake.
Icahn's unofficial position as a regulatory advisor to Trump drew criticism from conflicts-of-interest watchdogs immediately after it was announced last year. In May, eight Democratic senators asked U.S. regulators to investigate whether Icahn violated insider trading laws.
Icahn, who has argued he was acting in the interest of American energy security, stepped down from the advisory role in August. Icahn claimed the blending requirements threatened to put small refiners out of business and jeopardize the nation's ability to produce fuel.