Meet the 400 Richest Americans

It'll cost you at least $1.3 billion to join this club.

Sept. 17, 2008— -- The rich haven't gotten richer--or poorer--this year. The price of admission to this, the 27th edition of The Forbes 400, is $1.3 billion for the second year in a row. The assembled net worth of America's wealthiest rose by $30 billion--only 2%--to $1.57 trillion.

Rising prices of oil and art paved the way for 31 new members and eight returnees, while volatile stock and housing markets forced 33 plutocrats from our rankings.

Click here to learn more about America's richest people at our partner site, Forbes.com.

With a net worth of $57 billion, Bill Gates remains the richest man in America despite losing his crown to Warren Buffett for a few months this spring. Buffett's shares in Berkshire Hathaway have fallen 15% since February.

Newcomers to the list include fertilizer tycoon Alexander Rovt, car dealer and art collector Norman Braman and Patrón tequila founder John Paul DeJoria.

Also new: Mark Zuckerberg, the 24-year-old founder of social networking site Facebook, who debuts on The Forbes 400 with an estimated net worth of $1.5 billion.

Among the returnees are Urban Outfitters chief Richard Hayne and Gap founders Donald and Doris Fisher, who rode the swelling contemporary-art market back onto the list. The couple's art collection is believed to be worth more than $1 billion.

The Forbes 400 is a snapshot of estimated wealth on Aug. 29, 2008, the day we locked in prices of publicly traded stocks. Given how unsettled the stock market is, some of those on our list will become significantly richer or poorer within weeks--even days--of publication. Many, including AIG shareholders Eli Broad and Steven Udvar-Hazy, have lost hundreds of millions of dollars.

The average net worth of The Forbes 400 is $3.9 billion.

The biggest loser this year was casino mogul Sheldon Adelson, whose fortune has fallen $13 billion in the past 12 months--$1.5 million per hour--as shares of his Las Vegas Sands have dropped 75% from their all-time highs last October.

Fellow casino kingpin Kirk Kerkorian lost $6.8 billion this year as his stock in MGM Mirage fell 70% since last fall.

Other tycoons who have lost big bucks this year include Min Kao of global positioning system maker Garmin (down $2.9 billion), Google guys Sergey Brin and Larry Page (down $2.7 billion and $2.6 billion, respectively), eBay founder Pierre Omidyar (down $2.6 billion) and media maven Sumner Redstone (down $2.5 billion).

This year's biggest gainer is New York City Mayor Michael Bloomberg, whose estimated net worth rose $8.5 billion after he bought back a 20% stake in his financial data and news firm Bloomberg L.P. from Merrill Lynch this summer, finally putting a price tag on the private media outfit.

Several Forbes 400 veterans fell off the list this year. Among them: former AIG head Maurice (Hank) Greenberg and former eBay chief Margaret Whitman.

Two-thirds of the members of The Forbes 400 have fortunes that are entirely self-made, while only 19% of the group inherited their entire fortunes.

There are 42 women on the list with an average net worth of $4.2 billion. Oprah Winfrey saw her wealth increase $200 million to $2.7 billion.

Six members of last year's list died, including potato king John Simplot and building supplies magnate Kenneth Hendricks. He is replaced by his wife, Diane. Other deaths included medical device inventor James Sorenson and Cargill heir John Hugh MacMillan III.