Patrick Ryan

AGE: 74
OCCUPATION: CEO, Ryan Specialty Group

In January the insurance company this billionaire founded—Aon—decided to move its headquarters to London, potentially sticking him with a mammoth capital gains tax bill. But how many people can say they created from scratch a company with a $15.6 billion market cap?

RELATED: Most Powerful Ex-Chicagoans | Power Couples | Power Siblings | Up-and-Comers | Poll: Which Powerful Chicagoan Would You Call Back First? | Quiz: Do You Know Chicago’s Power Players? | Back to all 100


Photograph: Antonio Perez/Chicago Tribune