He later met value investor Benjamin Graham, one of the key influences on his investing style, at Columbia University. In 1965, he bought textile firm Berkshire Hathaway and eventually transformed it into massive company with holdings including food, insurance, utilities and industrials. Buffett acquired railroad giant BNSF Railway for $26 billion in 2009.
No. 3: Larry Ellison, $27 billion
Source of wealth: Oracle
Residence: Woodside, Calif.
Age: 66
2009 rank: No. 3
The Oracle (ORCL, news)chief made headlines recently when he brazenly chastised Hewlett-Packard (HPQ, news)for ousting chief Mark Hurd over his relationship with a marketing contractor. Then he hired Hurd to replace Oracle's co-president, Charles Phillips, who had resigned at the same time. HP sued Hurd, prompting Ellison to say that HP was making it "virtually impossible" for the two companies to do business together. (The two parties recently settled.)
Oracle, which has acquired 66 companies over the years, figured out a way to turn a profit on its latest big buy, Sun Microsystems, in 2010. One of the highest-paid executives in the country, Ellison has gotten $960 million in compensation in the past five fiscal years, mostly from the exercise of stock options; he recently cut his salary to $1.
Ellison's fortune is almost entirely tied up in Oracle; he also owns a $580 million stake in Web business-software outfit Netsuite (N, news)and is one of the largest private landowners in the celebrity haven Malibu, Calif. Ellison also has two houses in the Bay Area: a Japanese-style compound in Silicon Valley and a water-view mansion in San Francisco.
An avid yachtsman, Ellison spent a decade and more than $100 million on his quest for the America's Cup, which he finally won in February. He beat rival Ernesto Bertarelli, thanks in part to a trimaran with a rigid mainsail longer than a Boeing 747's wingspan. Now he's deciding where to hold the next Cup regatta and is said to favor the seas near his own backyard, San Francisco. He intends to give 95% of wealth to charity.
No. 4: Christy Walton and family, $24 billion
Source of wealth: Wal-Mart Stores
Residence: Jackson, Wyo.
Age: 55
2009 rank: No. 4
The widow of John Walton, one of the Walton family heirs, gained her wealth after the former Green Beret and Vietnam War medic died in an airplane accident in 2005 near his home in Wyoming. Christy Walton got an extra bump in her fortune because of her late husband's early investment in First Solar (FSLR, news); shares are up more than 400% since the company's initial public offering in 2006. But the bulk still comes from her shares in Wal-Mart Stores (WMT, news). An active philanthropist, Christy Walton supports museums, education and organic gardening.
Her father-in-law, Sam Walton, who died in 1992, founded the company in Bentonville, Ark., with his brother James in 1962. Today, Wal-Mart has annual sales of about $400 billion and employs more than 2.1 million people.
No. 5 (tie): Charles Koch, $21.5 billion
Sources of wealth: manufacturing, energy
Residence: Wichita, Kan.
Age: 74
2009 rank: No. 9 (tie)
Since inheriting control of the refining business built by his dad, Fred Koch, in 1967, Charles Koch has expanded the Wichita conglomerate more than 100-fold, to $100 billion in annual revenue. Koch Industries is now the second-largest private company in the U.S. behind Cargill. Koch's biggest deal to date: a $21 billion purchase of building-products-maker Georgia Pacific right before the housing market crashed. Charles and his brother David bought out siblings Frederick and William for $790 million in 1983.
