Herbalife shares sank 12 percent Monday, becoming one of the biggest losers in a day when the overall stock markets fell 2 percent.

The controversial diet-shake company closed at $33, its lowest level in more than two years on no news.

Almost 4 million shares traded hands, with selling coming from large stakeholders dumping huge blocks. Trading in options was equally large, which sources said looked like an effort by the sellers to trim their losses.

The slide put Carl Icahn in the red for the first time since he announced a 13 percent stake on Feb. 14, 2013.

Icahn, who now owns 17 million shares, is carrying a $68 million loss.

The company is in its quiet period prior to reporting earnings, which means that Icahn, an insider, wasn’t one of Monday’s big sellers.

Activist investor Bill Ackman, who now has a $2 billion short bet — after today’s stock slide — has an estimated profit of close to $200 million.