Shares of Herbalife plummeted on Tuesday.
Herbalife's stock fell 20.50%, or $11.46, to end the day at $44.44 per share.
Shares of the nutrition company opened lower on Tuesday following disappointing third-quarter results reported on Monday after the closing bell.
Earnings, revenue, and guidance all came in lower than Wall Street had expected.
Also, Herbalife on Friday agreed to pay $15 million to settle a class-action lawsuit filed by a former distributor who said the company was running a "pyramid scheme."
For nearly 23 months, hedge fund manager Bill Ackman, who runs Pershing Square Capital, has been crusading against Herbalife on the same allegation.
In December 2012, Ackman gave a 342-slide presentation publicly declaring that he was short $1 billion worth of Herbalife shares. Ackman contends that the company operates as a pyramid scheme that targets poor people. His investment thesis is predicated on regulators, specifically the Federal Trade Commission, shutting the company down. (The FTC opened an investigation into the company back in March.)
He said he would short the company to zero.
But after Ackman's initial presentation, numerous fund managers, most notably Ackman's longtime rival Carl Icahn, piled on by going long the stock. Since then it's been a crazy ride up and down.
Here's a five-day chart of the stock's performance:
Here's how the stock has performed since Ackman made his short public:
SEE ALSO: We Have Never Seen Anything Like Bill Ackman's Dizzying Takedown Of Herbalife