Herbalife Ltd., the Los Angeles-based maker of nutritional and weight-loss supplements, has been at the center of a Wall Street grudge match, with hedge fund manager Bill Ackman betting it will fail and billionaire investor Carl Icahn saying it won't. Ackman, who took a $1 billion short against Herbalife shares in December, said the company is a fraudulent pyramid scheme in which most of its distributors make no money. Herbalife -- and Icahn -- deny the allegations, saying the company's business model is sound, and legal. Founded in 1980, Herbalife sells its products through a team of independent distributors in more than 80 countries. These distributors make money from their own sales as well as for those made by distributors they recruit.