Carl Icahn resigned Friday from an unpaid position as President Trump's advisor on deregulation. Getty

President Donald Trump has mostly surrounded himself with advisors and a Cabinet who boast billions in personal wealth. On Friday, perhaps lost amid the high-profile exit of chief strategist Steve Bannon, financier Carl Icahn, the wealthiest of Trump's circle, announced he would no longer serve as a special advisor on financial regulation after criticism from biofuel advocates and Democratic lawmakers claimed his policy recommendations could help his own investments.

In a letter to Trump on his personal website, Icahn, an 81-year-old corporate raider with a net worth of roughly $16 billion, denied any conflict of interest with his businesses, claiming he "never had access to nonpublic information or profited" from his position after accusations from several Democratic lawmakers, who claim he pushed for changes in biofuel policy for his “own personal gain.” He also claimed he was resigning to avoid "partisan bickering."

"I never had a formal position with your administration nor a policymaking role," read the letter to Trump. "And contrary to the insinuations of a handful of your Democratic critics, I never had access to nonpublic information or profited from my position, nor do I believe that my role presented conflicts of interest. Indeed, out of an abundance of caution, the only issues I ever discussed with you were broad matters of policy affecting the refining industry. I never sought any special benefit for any company with which I have been involved, and have only expressed views that I believed would benefit the refining industry as a whole."

Icahn stepped down before the New Yorker published a report Friday by Patrick Radden Keefe that cited Bush administration ethics lawyer Richard Painter's claim that Icahn could be in "legal jeopardy" and that he is "walking right into possible criminal charges" for pressuring the Environmental Protection Agency (EPA) to change federal regulations that affect oil refiner CVR Energy. Icahn reportedly holds an 82-percent stake in the Sugar Land, Texas-based company, acquiring a controlling interest in 2012.

The federal regulations stem from Renewable Fuel Standard (RFS), a law signed in 2005 requiring transportation fuel to contain a minimum volume of renewable fuels. According to the New Yorker report, when the price of Renew Identification Numbers (RIN) began fluctuating in 2013, CVR Energy was spending over $200 million a year on credits.

In March, the New York Times reported that Icahn had discussed ethanol rules with Scott Pruitt prior to Pruitt becoming head of the EPA. Icahn also spoke with Trump and his top economic advisor, Gary Cohn, about ethanol.

As a candidate in the 2016 Presidential Election, Trump had said he would nominate Icahn for secretary of the treasury. The position ultimately went to banker Steve Mnuchin, who is reportedly worth $300 million.

Phone calls to CVR by International Business Times on Saturday were not answered.