Dropped out of engineering studies to immigrate from Hungary
Interactive Brokers Group
Born during a Russian bombing raid in 1944, Thomas Peterffy moved to New York in 1965, as a refugee from communist Hungary. He spoke no English when he arrived, but found a job as a draftsman, according to Forbes. In 1977, he bought a seat on the American Stock Exchange and shocked traders in the early 80s when he brought an early handheld computer to the floor. The company that eventually grew out of that seat on the AMEX became Interactive Brokers Group
. According to a November of 2005 profile in Interactive Brokers, Peterffy wrote computer code in his head while trading during the day then went back to the office later to apply computer models to trading. Those early uses of computers made him a pioneer in the field. Today, the company website claims Interactive Brokers logs more than one million trades per day.
(Editor's note: This caption has been updated to cite Forbes magazine.)