Seth Merrin is the billionaire founder and CEO of Liquidnet, a "dark pool" system that allows institutional investors to trade large blocks of securities without wild swings in prices. He started that company after selling another, Merrin Financial, for $23 million in 1996. He Grew up wealthy on New York's Upper West Side as father owned a gallery that sold ancient art. In 2008 he made the Forbes List of the 400 wealthiest Americans at #377 with a net worth of $1.3 billion. He owns this 11,111 sq ft home.
http://www.dailymail.co.uk/news/article-2550960/Beloved-philanthropist-orphaned-Rwandan-children-called-Big-Momma-dies-falling-horse.html