Jim Simons' net worth swelled to $10.6 billion – up from $8.7 billion in September of 2010 – and he retained his position as the No. 30 richest person in America on the Forbes 400 list, released earlier this week.
Simons, who lives in East Setauket, started hedge fund firm Renaissance Technologies in 1982 and retired in 2009. Renaissance Technologies is worth $15 billion, according to Forbes.
In 2009, when his net worth was $8.5 billion, he was No. 29 on last year's list. He was No. 41 in 2008, when his net worth amounted to $7.4 million.