A former director of a global management consulting firm pleaded guilty Thursday to securities fraud charges, admitting making $2.6 million by feeding inside stock information to one of America’s richest men in history’s largest hedge-fund insider trading case.

Anil Kumar, 51, of Saratoga, Calif., entered the plea in U.S. District Court for the Southern District of New York in a cooperation deal aimed at strengthening the government’s case against billionaire hedge-fund operator Raj Rajaratnam.