First published in 1982, every year the Forbes 400 lists the 400 wealthiest Americans.

September 2009, for the first time in 7 years, the wealthiest Americans have lost money. The net worth of the Forbes 400 dropped from 1.57 trillion to 1.27 trillion, a loss of 300 billion from the year before. Bill Gates topped the list but lost 7 billion, followed by Warren Buffett who lost 10 billion since September 2008. http://www.nydailynews.com/money/work_career/2009/09/30/2009-09-30_bill_gates_warren_buffett_lawrence_ellison_top_2009s_forbes_400_richest_american.html

After releasing their annual list in September 2008, the money magazine recalculated the list in October to take into account the September financial turmoil on the 400's worth. According to the magazine, Warren Buffett added $8 billion to his net worth during the time period in question, while others lost billions.Los Angeles Times: Forbes 400 list recalculated; Warren Buffett now the richest American (October 9, 2008)