NEW YORK (Reuters) - Billionaire investor Carl Icahn’s multimillion-dollar bet against U.S. biofuel prices is looking increasingly risky in the wake of a Friday court ruling that will likely boost the cost of complying with the program.

File photo: Billionaire activist-investor Carl Icahn gives an interview on FOX Business Network's Neil Cavuto show in New York, U.S. on February 11, 2014. REUTERS/Brendan McDermid/File Photo

CVR Energy CVR.N, majority owned by Icahn, said Friday that its short position in the U.S. biofuels market grew to a record $279.9 million at the end of the second quarter, up from $182.2 million on Jan. 1.

The independent refiner lacks blending facilities and must buy biofuel credits, or RINs, exposing it and other refiners to market prices. Refiners can defer buying credits for months, or years, in hopes that prices will fall. CVR chose the latter strategy in the last year, making it the “most RIN-exposed” U.S. refiner, said Tudor, Pickering and Holt analysts.

That bet reaped a rare profit in the first quarter, as prices dropped on optimism that Icahn, as an adviser to President Donald Trump, would get the program changed - a controversial relationship that has spurred calls by Senate Democrats for an investigation.

So far, the U.S. Environmental Protection Agency has kept the program unchanged. On Friday, a U.S. appeals court said the EPA should reconsider a 2014 decision to lower the amount of biofuels required to blend into the nation’s fuel pool. RIN prices are up from a low of 34 cents in mid-March to new yearly highs of 89 cents on Friday.

The court decision “seems likely to support prices” of the credits, said Neelesh Nerurkar, of research firm ClearView Energy Partners LLC in Washington.

CVR declined comment.

The EPA’s U.S. Renewable Fuel Standard (RFS) requires biofuels such as ethanol to be blended into the nation’s gasoline and diesel. Fuel importers and refiners either blend the fuels or purchase credits from others that have.

CVR Refining LP is on track to pay a record amount in 2017, the company said last week.

The company is a variable master limited partnership, which means it is not required to distribute cash to investors. It has not issued a distribution since March 2016, around when it started building its biofuels short position.

CVR Refining’ s cash balance was $515.7 million at the end of the second quarter, up from $145.9 million in March 2016, largely due to not buying RINs, a Reuters analysis shows.

Shares of parent CVR Energy CVI.N closed Monday at $18.91 a share, down more than 25 percent this year.