No. 17 Thomas Peterffy
581,000 acres (up 20,000 acres)
This Hungarian refugee arrived in New York City in 1965 and soon began trading options on the American Stock Exchange. Ultimately, Peterffy made a name for himself by automating the trading floor with handheld computers. He then founded the electronic brokerage firm Interactive Brokers. Forbes consistently ranks the innovator as one of the world’s richest billionaires. In December 2015, Peterffy vaulted into the top tier of US landowners when he paid more than $700 million to acquire 561,000-acre FOLEY TIMBER & LAND in Northern Florida.