An escalating battle of hedge fund titans over whether nutritional and vitamin supplements company Herbalife is a legitimate business or a scam has so far pulled in Am Law 100 firms Boies, Schiller & Flexner and Kirkland & Ellis.

The dispute kicked off in earnest in late December, when Los Angeles–based Herbalife retained Boies Schiller amid an offensive against hedge fund magnate William Ackman of Pershing Square Capital Management after he publicly announced a $1 billion bet against a company he claims is nothing more than a pyramid scheme. Ackman said it was his “patriotic” duty to take down Herbalife and its CEO, Michael Johnson, whose nearly $90 million in 2011 compensation made him the country’s highest-paid corporate executive that year.