Jeff Yass of the Susquehanna International Group

Founder: Susquehanna International Group
Like the professional poker player he once was, Jeff Yass — now a leading figure in the national stock options markets — keeps his cards close to the vest. As an 11-year-old boy, he checked stock quotes the way other kids scan box scores, persuading his father to buy him 10 shares of Campbell's after he learned they made Swanson TV dinners. In 1987, he and six other traders founded Bala Cynwyd-based Susquehanna, which now handles roughly one out of every seven stock options traded in the world as well as almost three percent of the volume on the New York Stock Exchange. When competition heated up two years ago as options exchanges began to list one another's companies, it was Yass who conceived of paying brokerages to steer orders his way — a legal kickback that has nonetheless drawn the scrutiny of the sec. Working the probabilities and shifting the odds in his favor remain the obsessions of a man who reportedly still requires new employees to read a book on gaming theory. "Jeff doesn't want to be the gambler," says one friend on the exchange. "He wants to be the casino."

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