When the President announced last week that his Administration will impose hefty new tariffs on foreign steel and aluminum imports, the stock market and even many of his own economic team appeared thrown off balance.

But not, it appears, his one-time White House advisor, billionaire investor Carl Icahn.

In the weeks leading up to Trump’s announcement, Icahn sold off over $30 million of stock in Manitowoc Company—a crane manufacturer that relies on imported steel—according to Securities and Exchange Commission (SEC) records first reported by ThinkProgress.

The sales were the first time Icahn traded his Manitowoc stock in more than three years, according to SEC records, and they drew the suspicion of many—including the Project On Government Oversight. On Monday, POGO sent the SEC a letter asking the agency to investigate if Icahn was inappropriately tipped off to the President’s plan and if he used that information for his own profit.

Icahn started dumping nearly a million shares of Manitowoc Company stock on February 12, when it was trading at $34.31 per share, according to a filing with the SEC on February 22. Manitowoc’s trading price dipped more than 6 percent in the wake of Trump’s tariff announcement, per Reuters.

The Manitowoc episode is just the latest example where Icahn’s actions raise questions about blurred ethical boundaries in an Administration where all too often the line between personal profit and policy priorities appears muddied.

Icahn took up a poorly defined role as “Special Advisor” to President Trump on regulatory issues shortly after the 2016 election. Despite his official title, Trump’s press release announcing Icahn’s position also explicitly noted that he was not going to be a “special government employee” and thus would not be subject to the ethics rules such employees face.

He helped vet Trump’s picks to agencies, such as Environmental Protection Agency chief Scott Pruitt and SEC Chairman Jay Clayton—both of whom now run agencies with the regulatory power to impact some of Icahn’s investments and are in positions to investigate Icahn’s companies. POGO’s insider trading complaint to the SEC regarding Icahn is a case in point.

Icahn’s role and his activities drew scrutiny from good government groups and some Senators, who pressed Icahn and the Administration on how it was handling potential conflicts of interest with Icahn. For example, last July, Senators Elizabeth Warren (D-MA) and Sheldon Whitehouse (D-RI), wrote to Treasury Secretary Steven Mnuchin asking for information about contacts between Icahn and members of a financial oversight board with sway over AIG, another company in Icahn’s financial portfolio.

Icahn ultimately resigned last August, shortly before the publication of an extensive New Yorker report that detailed how Icahn allegedly tried to leverage his connection with the White House to push for a regulatory change that would have benefited his own investment in a Texas oil refinery.

In a statement at the time, Icahn denied having any “formal position” or “policymaking role” in the Administration. “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,” he wrote.

But despite Icahn’s protestations, government investigators seem to be taking concerns seriously. In a November filing, his firm Icahn Enterprises disclosed it had been subpoenaed for information about his activities in connection with his White House role.

Hopefully, the questions POGO and others are asking about Icahn’s Manitowoc trading will also be investigated thoroughly. However, even more important than determining whether or not there was wrongdoing in this particular instance is fostering an environment that doesn’t allow for the possibility of such conflicts in the first place. Americans deserve to know that their government is operating in the public interest—and that will only happen if the Administration stops allowing some to operate in “ethical gray zones.”