Bill Gates is the richest American for the 20th year in a row and has reclaimed the title from Mexico's Carlos Slim with a net worth of $72 billion.
Warren Buffett was number two after having added $12.5 billion to his fortune.
In the technology field, Larry Ellison is following Gates and took the second spot while Amazon CEO Jeff Bezos added $4 billion to his net worth in the last year to follow the Oracle CEO with a net worth of $27.2 billion. Larry Page and Sergey Brin were placed fourth and fifth among the American tech billionaires.
Facebook?s Mark Zuckerberg is back into the top 20 after missing the top cut last year. Carl Icahn may lost his battle to stop Dell from going private but he had a great year and moves back in the top 20 for the first time since 2008.
Steve Ballmer, now worth $18 billion, ranks in at No. 21. He saw a $2.1 billion rise of his net worth over the past year, a figure boosted by a stock bump that came after he announced he?d be stepping down as CEO of the software giant.
According to Forbes, the 400 wealthiest Americans are worth a record $2.02 trillion, roughly equivalent to the GDP of Russia. That is a gain of $300 billion from a year ago, and more than double a decade ago. The average net worth of list members is a staggering $5 billion, $800 million more than a year ago and also a record.