Icahn Enterprises L.P. IEP disclosed Wednesday in its 10-Q quarterly filing that on May 3, it was contacted by the U.S. regulators, seeking information, including materials on corporate governance, capitalization, securities offerings and valuation. The investigation by the U.S. Attorney’s office of the Southern District of New York comes a day after short-seller Hindenburg Research issued a report questioning the company’s valuation, with Icahn responding by saying it stood by its public disclosures. Icahn said in the 10-Q that it was cooperating with the investigation. “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 company said in the 10-Q. “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.” The stock tumbled 15.7% in morning trading Wednesday, and has plunged 36.5% since the Hindenburg report was released.

Market Pulse Stories are Rapid-fire, short news bursts on stocks and markets as they move. Visit MarketWatch.com for more information on this news.