Citadel Founder and CEO Ken Griffin is one of the most successful investors of all time, managing over $62 billion in assets. He is also the founder of Citadel Securities, the largest market-making firm for the New York Stock Exchange and one of the largest designated market makers in the world. Citadel Securities is involved in one out of four stock trades placed in U.S. exchanges and nearly 40% of all retail trades. With a net worth of $37.5 billion, Griffin is one of the richest hedge fund managers in the world and is ranked No.