Richest 400 Americans' net worth jumps 13%

The cover of the Forbes 400 issue on philanthropy is shown in this handout photo supplied to...

The cover of the Forbes 400 issue on philanthropy is shown in this handout photo supplied to Reuters September 18, 2012 featuring 12 of the more than 150 influential entrepreneurs the magazine brought together for a private discussion on ways to help solve some of the world's most intractable problems. From Warren Buffett and Oprah to Bill and Melinda Gates, some of the world's greatest philanthropists with a combined net worth of $126 billion attended the summit. The Forbes 400 issue goes on sale September 21, 2012. (REUTERS/Forbes/Handout)

Dan Burns, Reuters

, Last Updated: 3:58 PM ET

NEW YORK - The net worth of the richest Americans grew by 13% in the past year to $1.7 trillion, Forbes magazine said on Wednesday, and a familiar cast of characters once again populated the top of the magazine’s annual list of the U.S. uber-elite, including Bill Gates, Warren Buffett, Larry Ellison and the Koch brothers.

The average net worth of the 400 wealthiest Americans rose to a record $4.2 billion, the magazine said.

Collectively, this group’s net worth is the equivalent of one-eighth of the entire U.S. economy, which stood at $13.56 billion in real terms according to the latest government data. But the 13% growth in the wealth of the richest Americans far outpaced that of the economy overall, helping widen the chasm between rich and poor.

Bill Gates, the chairman of Microsoft Corp, topped the list for the 19th year in a row with $66 billion, up $7 billion from a year earlier.

Warren Buffett, chairman and chief executive of insurance conglomerate Berkshire Hathaway Inc, stood second with $46 billion, followed by Larry Ellison, head of software maker Oracle Corp, with $41 billion; and the Koch brothers, Charles and David, who run the energy and chemicals conglomerate that bears their name, Koch Industries, were tied for fourth with $31 billion, Forbes said.

The ranks of the top five were unchanged from a year earlier.

Two notable names dropped from the top 10, however. Casino magnate Sheldon Adelson, also active in conservative political causes, fell to the 12 spot from No. 8 last year, and financier George Soros dropped five spots to No. 12 from the No. 7 position one year ago.

The disappointing stock market debut of Facebook Inc also took a toll on the fortune of its founder and CEO, Mark Zuckerberg. His net worth fell by nearly half to $9.4 billion, and he slid to the No. 36 slot from No. 14 a year ago, Forbes said.

Forbes list of America’s richest people

Below are the top 10, as estimated by the magazine. The full list can be seen at

1. Bill Gates, Medina, Wash., $66 billion

2. Warren Buffett, Omaha, $46 billion

3. Larry Ellison, Woodside, Calif., $41 billion

4. Charles Koch, Wichita, Kan., $31 billion

5. David Koch, New York City, $31 billion

6. Christy Walton & family, Jackson, Wyo., $27.9 billion

7. Jim Walton, Bentonville, Ark., $26.8 billion

8. Alice Walton, Fort Worth, Texas, $26.3 billion

9. S. Robson Walton, Bentonville, Ark., $26.1 billion

10. Michael Bloomberg, New York City, $25 billion