(Reuters) – Shares of Icahn Enterprises, the company of billionaire investor Carl Icahn, closed at a more than 20-year low on Monday after the company said it would sell up to $400 million worth of depositary units in an at-the-market offering program.

The stock fell by as much as 14.3 percent to $13.62, the lowest level since November 2003. However, it was able to reduce its losses and closed with a loss of 11.5 percent at $14.07, the weakest price since February 2004.

About 6.8 million shares changed hands, making it the busiest session in just over a year.

The company said in a regulatory filing that it intends to use the net proceeds from the offering to fund potential acquisitions and for corporate purposes.

There was no immediate comment on a call from Icahn’s office on Monday afternoon.

Icahn and his company reached a settlement with U.S. regulators last week for failing to disclose for years that he had pledged most of the company’s securities for billions in private loans. They jointly agreed to pay a $2 million penalty.

Icahn Enterprises is still locked in a feud with short-seller Hindenburg Research, which last year accused Icahn of running a “Ponzi-like” scheme to pay out dividends by overvaluing his holdings. Hindenburg also raised questions about Icahn’s margin loans.

According to a separate statement, Jefferies is acting as selling agent for the stock sale program for Icahn Enterprises.

Jefferies is the only brokerage covering the company, giving it a “buy” rating and a $25 price target, according to LSEG data.

(Reporting by Jaiveer Singh Shekhawat in Bengaluru and Lance Tupper in New York; additional reporting by Carolina Mandl; editing by Richard Chang)