BOSTON (Reuters) - Investor Jeffrey Tarrant, whose firm Protege Partners backed billionaire managers including William Ackman and Marc Lasry early in their careers and made a bet with Warren Buffett that hedge funds would outperform a passive index fund, has died at age 63. Tarrant died on Aug. 5 at his home in Bridgehampton, New York, his firm said, giving the cause of death as brain cancer. Over 17 years, Tarrant turned Protege Partners into a powerful backer of small hedge funds, often identifying and seeding portfolios before they became widely known and successful.