The 13,172‑sq‑ft main house sits on a 438,000‑sq‑ft lot and was built in 1910, making it one of the few private homes in Westchester that straddles three municipal boundaries. It sits at 350 Purchase St., touching the city of Rye, the village of Rye Brook and the town of Harrison. The property’s layout has earned it a spot on the Rye‑Harrison News list of unique local landmarks.
The estate’s interior boasts 14 bedrooms, two swimming pools, a clay tennis court, several beehives and a private stream that feeds a lake stocked with fish. A 2007 New York Post profile described the mansion in detail, noting its expansive grounds and luxury amenities.
Tax records from 2007 reveal Thain paid more than $150,000 each year to Harrison and Rye combined. A local resident told the Post that the estate’s sheer size was hard to fathom, saying it would take him 20 minutes to circle from front to back. The property’s cross‑town status complicates paperwork and billing for utilities and services.
Prior to purchasing the Westchester estate, Thain climbed Wall Street’s ranks, serving as president and co‑chief operating officer at Goldman Sachs, then CEO of the NYSE from 2004 to 2007. He later became chairman and CEO of Merrill Lynch during the 2008 financial crisis, overseeing its $50 billion sale to Bank of America.
After leaving Merrill Lynch, Thain joined CIT Group as chairman and CEO in 2010, guiding the company through bankruptcy recovery before retiring in 2016. He has since sat on boards such as Uber’s, and with the New York Botanical Garden, where he and his wife fund conservation projects. The Purchase Street estate remains his primary residence, anchoring him to the three Westchester communities.