Carl Icahn’s Icahn Enterprises (IEP) stock tanked on Wednesday after the company revealed in an SEC filing it’s under investigation from federal prosecutors.

The U.S. Attorney's office for the Southern District of New York contacted Icahn the day after Hindenburg Research released a short-seller report accusing Icahn Enterprises of a “Ponzi-like” structure.

The federal prosecutors sought information about dividends and corporate governance, among other topics, according to an SEC filing released on Wednesday.

Icahn Enterprise shares closed down 15.1% on Wednesday in response to the news and are now down roughly 40% since the report.

Icahn and “affiliates” own approximately 84% of Icahn Enterprises, according to a release. The slump in IEP shares have sent Icahn’s net worth down nearly 40%, according to Bloomberg’s billionaires index.

Hindenburg highlighted IEP’s 15.8% dividend yield, which it said is the largest of any U.S. large cap name. Hindenburg argued that achieving that yield isn’t being done through legal means and Icahn is “taking on too much leverage.”

Icahn hasn’t spoken publicly since the accusations outside of prepared statements. Icahn released an updated statement on Wednesday.

"Hindenburg Research, founded by Nathan Anderson, would be more aptly named Blitzkrieg Research given its tactics of wantonly destroying property and harming innocent civilians,” Icahn said in the statement. “Mr. Anderson's modus operandi is to launch disinformation campaigns to distort companies' images, damage their reputations and bleed the hard-earned savings of individual investors. But, unlike many of its victims, we will not stand by idly. We intend to take all appropriate steps to protect our unitholders and fight back.”

In Wednesday’s filing, IEP said it’s cooperating and providing documents to federal prosecutors.

“The U.S. Attorney’s office has not made any claims or allegations against us or Mr. Icahn with respect to the foregoing inquiry,” the filing read. “We believe that we maintain a strong compliance program and, while no assurances can be made and we are still evaluating the matter, we do not currently believe this inquiry will have a material impact on our business, financial condition, results of operations or cash flows."

Josh is a reporter for Yahoo Finance.

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