Hedge fund manager, billionaire, and special adviser on regulatory reform to President Donald Trump, Carl Icahn, has been named in a complaint submitted to Congress today alleging that the 81-year-old investor "violated lobbying rules" for his suggestions that the White House change the Environmental Protection Agency's Renewable Fuel Standard -- a change that Politico reports would save Icahn "hundreds of millions of dollars." The complaint was authored by consumer watchdog Public Citizen, who stated that Icahn Enterprises, and Icahn himself, "failed to register as lobbyists," even as they advocated that the Trump administration strike EPA rules that have existed for decades.

The advocacy group is asking Congress to conduct an investigation into the Trump-Icahn link.

CNBC describes the Donald Trump-Carl Icahn relationship as one of friendship. Early in Donald Trump's presidential campaign, the then-candidate spoke publicly about nominating Icahn as Treasury secretary if he won. At the time, in the summer of 2015, Icahn indicated that he would turn down the president's offer, but that he would "certainly be there to advise him if he wanted it." After Trump won the November election, Forbes reported that he formally asked Icahn to serve as his "special adviser." Under the role, which Icahn accepted, the businessman, who is reported to have a net worth of $22 billion, is not a federal employee, and receives no compensation.

Icahn-Trump reforms could save billionaire 'hundreds of millions of dollars'

Capitol Hill Blue reports that Icahn Enterprises holds an 82-percent stake in CVR Energy, Inc. (NYSE: CVR), and has called for reforms that would move regulatory burdens from refiners to wholesalers. Carl Icahn has described the move benefiting not only CVR, "but the entire refining industry." Public Citizen's letter, which was addressed to the secretary of the Senate and the clerk of the House, also cited Carl Icahn's involvement in the selection of the new EPA head, former Oklahoma Attorney General Scott Pruitt, and language used in a memo to the EPA discussing changes that Icahn was involved in.

Another oil-refining business, Valero Energy Corporation (NYSE: VLO), was also said to be involved in authoring language used in the memo from the White House to the EPA. Trailing 12-month revenue for Valero is reported by Yahoo Finance at $70.17 billion; CVR has generated $4.78 billion in revenue, over the same period.

'Unlikely' Carl Icahn, associates not required to disclose lobbying activities

The letter to Congress is said to state that it is "unlikely that all these activities occurred without some individual or entity being obligated to report lobbying activity under the" Lobbying Disclosures Act. The law was enacted in 1995, and requires lobbyists engaged in activity similar to what is being reported between President Trump and Carl Icahn to register and disclose conversations conducted with, and proposals submitted to, officials, such as the president of the United States. In February, Carl Icahn submitted a formal proposal to the White House, seeking his industry reforms. Politico calls the episode "the latest" in a series of "ethical complications" that have entangled the president and his cabinet, "because of their myriad business holdings."