No. 1 Warren Buffett BERKSHIRE HATHAWAY
By Andy Serwer REPORTER ASSOCIATES Brenda Cherry, Muoi Tran

(FORTUNE Magazine) – The most powerful businessperson in America is famously understated about his station in life. Sure, Warren Buffett enjoys some of the trappings that come from being the second-richest man in the world, such as winging around in one of his Netjets and playing bridge with pal (and No. 2 on our list) Bill Gates. Mostly, though, the 72-year-old brushes aside the notion that he is the Atlas of American business. "It really just means that if I do something dumb, I can do it on a very big scale," he says with his trademark chuckle. "It means you could add a lot of zeros to the losses."

There haven't been many of the latter. Buffett's company, Berkshire Hathaway, has become an all-American juggernaut, with multibillion-dollar interests in everything from insurance--where Buffett is one of the world's leading players--to newspapers, carpets, and cowboy boots. In racking up compound annual returns of 21% over the past 15 years (vs. the market's 11%), Buffett has proved himself the world's greatest investor. As such, his influence on stocks and the market is unparalleled. Word that Buffett is buying or selling certain shares (be it fact or fiction) will move a stock like a pinball, which is why he is extra-guarded when it comes to discussing investments.

One of the few places where he does talk about investments--his annual letter to shareholders--is far and away the most widely read communication from a CEO in the world. When former Chinese President Jiang Zemin discussed the mystifying nature of the U.S. stock market with a visiting Bill Gates, Gates told him that there was really only one guy who understood it: Warren Buffett. Gates added that when he got back to the U.S., he would send Buffett's most recent annual report to him. Which he did. (No word on whether Jiang is now long BRK.)

What's more, Buffett is without question the world's most sought-after businessman by other CEOs who want guidance. "CEOs are surrounded by people who are getting paid," says Buffett. "I'm getting nothing, so I can give them unbiased advice." Over the past five years dozens of CEOs have come to Omaha to visit the sage, including General Electric's Jeff Immelt (No. 7 on our list). "I've been there two or three times to speak with him and have a steak," says Immelt. "He's the world's most astute investor, and I'm trying to pick his brain."

The U.S. Congress hangs on Buffett's words too. On May 20, just days before lawmakers voted on the Bush tax bill, Buffett wrote an op-ed piece in the Washington Post that pointed out what he perceived as the folly of eliminating taxes on dividends. The tax cut, Buffett argued, would mostly benefit the wealthy. Powerful stuff coming from Buffett--powerful enough to persuade certain members of Congress to water down the final version of the tax cut.

Quite simply, Buffett is respected and admired more than any other businessperson alive, not only by others in business but by the general public as well. Now that's power. --Andy Serwer