Michael Milken is an American financier and philanthropist, best known for his role in the development of the high-yield bond market in the 1980s. He worked at Drexel Burnham Lambert, where he pioneered the use of junk bonds to finance corporate takeovers and expansions, significantly impacting the investment landscape. In 1989, Milken was indicted for securities fraud and conspiracy, leading to a guilty plea and a prison sentence. After serving time, he became a prominent philanthropist, focusing on medical research and education through the Milken Institute, which he founded to promote innovative solutions to global challenges.