Thomas Peterffy's Estate

Peterffy is the billionaire founder and head of Interactive Brokers, an online discount brokerage firm. He purchased this 80-acre property including a small village of buildings in 2004 for $45 million. The property includes a 8,038-square-foot mansion, guest houses, a caretaker's cottage, a horse stable, and is surrounded by farmland and woods. He also owns other property in Greenwich.

As of May 2014, Forbes ranks him among the 50 richest Americans, with a personal wealth of $8.7 billion.