SUSAN GOLDMAN

A worker cleans the logo on the Herbalife sign as finishing touches are put on the company's building in Torrance, Calif. Herbalife came out swinging Thursday, Jan. 10, 2013 against claims made by hedge fund manager William Ackman that the business amounts to a pyramid scheme.

The L.A.-based company, Herbalife, makes billions of dollars selling nutritional supplements all over the world; the company did $3.5 billion in net sales last year.

Sounds profitable, yet hedge fund manager and activist investor Bill Ackman is betting that Herbalife stock will soon be worth zero. With us to explain is KPCC's business reporter Matt Debord.