Shares sank 19% Wednesday, adding to a 20% plunge in the prior session when a Hindenburg Research report sent the stock spiraling in its worst one-day drop on record. Carl Icahn, who is chairman of the board at the holding company, saw billions erased from his fortune by the rout, as Hindenburg took aim at one of Wall Street’s most famous activist investors.

A rebuttal on Tuesday from its billionaire chairman did little to stem the selloff. 

“The self-serving short seller report published by Hindenburg Research today was intended solely to generate profits on Hindenburg’s short position at the expense of IEP’s long-term unitholders,” Icahn said in a statement. “We stand by our public disclosures and we believe that IEP’s performance will speak for itself over the long term as it always has.”

Hindenburg, founded by Nathan Anderson, has risen to prominence targeting corporate giants like payments firm Block Inc. and billionaire Gautam Adani’s business empire. In the report, Hindenburg said that Icahn “has made a classic mistake of taking on too much leverage in the face of sustained losses: a combination that rarely ends well.”