Shares in Herbalife were up as much as 15% as Pershing Square's Bill Ackman delivered what he said yesterday was the most important presentation of his career on the nutritional-supplement company. 

Appearing on CNBC Monday afternoon, Ackman reiterated his assertion that the Grand Cayman-based firm's business model doesn't add up and that its shares were going to zero. 

Shares fell $6 yesterday.

Herbalife has gained 33% since December 2012 when Ackman published a 334-page document he said showed the company was a fraud. 

Here's the chart:

Click here to follow Julia LaRoche's live coverage of today's presentation »

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