Forbes: James Simons, Ira Rennert among richest LIers

James Simons, the one-time math professor and military code breaker who made a fortune applying his dizzying gift for numbers to financial markets, remains Long Island's richest man, according to Forbes' 2012 list of the 400 wealthiest Americans.

With a net worth of $11 billion, the East Setauket resident is 28th on the overall list, and among five Long Islanders in the elite club. The others are junk-bond guru Ira Rennert, Cablevision's Charles Dolan and family, investment banker Kenneth Langone and hedge fund manager Louis Bacon.

Microsoft founder Bill Gates took Forbes' top spot for the 19th year running, with $66 billion to his name. Ranking No. 10 on the list, at a net worth of $25 billion -- up $5.5 billion from a year earlier -- was New York City Mayor Michael Bloomberg, founder of financial information and news service Bloomberg LP.

Simons, 74, who has been the richest Long Islander for several years, ran Stony Brook University's math department before founding Renaissance Technologies Corp. in 1982. The company uses computer algorithms to profit from securities trading.

Rennert, 78, is No. 52 with $6.5 billion. He owns one of the nation's largest holding companies. His Sagaponack home is among America's biggest.

Dolan, 85, is 132nd; he and his family are listed at $3 billion. The Oyster Bay resident founded the network that became HBO, then traded it for the company that became Cablevision; it owns Newsday.

Langone, 77, is 298th with $1.6 billion. The Sands Point resident helped found The Home Depot. Thanks to a $200 million gift, New York University's Langone Medical Center bears his name.

Bacon, 54, is 347th with $1.3 billion. He helped preserve much of Peconic Bay's Robins Island.