Michael Milken, the former junk bond financier who now runs the Milken Institute economic think tank in Santa Monica, is one of seventeen billionaires who have pledged to give the majority of their wealth to charity. Milken joined Facebook CEO Mark Zuckerberg and others in taking the Giving Pledge on Wednesday, an effort co-founded by Warren Buffett and Bill and Melinda Gates, to get America's wealthiest families to focus on philanthropy. Milken is worth around $2.5 billion, according to the Forbes list of the richest people in the world.