He’s the richest person in Illinois and already has several homes. Not long ago, he bought several floors of a Chicago condominium for almost $59 million.

Who is this guy? Ken Griffin is the founder of the Citadel hedge fund. A Harvard grad who started investing from his dorm room when he was 19. Today he’s worth about $10 billion.

Believe it or not, there are 44 people in the country even richer than he is!

His latest purchase is a 24,000 square foot apartment in New York City at 220 Central Park South. The price was $238 million – making it the highest-priced home ever sold in the U.S.

And you thought your mortgage payments were huge!