Digital trading pioneer Thomas Peterffy just listed his gigantic Greenwich estate for $65 million

Thomas Peterffy is a billionaire that made his fortune in the stock market - but not in the traditional way. Peterffy? was instrumental in bringing electronic trading to reality in the late 20th century.

Now he's selling his 80-acre estate in one of the most exclusive gated communities in Connecticut for $65 million - $20 million more than he paid for it in 2004, according to The Wall Street Journal. The Conyers Farm estate has three guest cottages and a 22-slot horse stable (where? ?Peterffy kept six horses), in addition to a 8,000-square-foot main residence.

Peterffy is selling the house because he no longer uses it as his primary residence.

David Ogilvy of David Ogilvy & Associates, associated with Christie's International Real Estate, has the listing.