The billionaire investor known as the "Oracle of Omaha" is Anheuser-Busch's second-largest shareholder, controlling almost 5 percent of its stock through his Berkshire Hathaway Inc. — worth about $2.3 billion if the deal is completed. Only Barclays PLC has a larger interest.

Mathematically, Buffett can't block a sale if other stockholders favor InBev's $65-a-share offer, even when combined with the 4.5 percent stake held by A-B's directors and executive officers.

But his supersized influence on Wall Street, a product of decades of savvy stock picking and a cult following, makes him a pivotal figure who potentially could derail or bless InBev's takeover attempt.

"The truth is he has a halo effect around him, and what he says generally goes," said Andy Kilpatrick, author of two books about Buffett. "The track record is that his opinion is likely to be the correct opinion. If he swings his votes, other people would vote with him and the Busches might say the game is up."

Adolphus Busch IV, an uncle of Anheuser-Busch Chief Executive August A. Busch IV, said as much in a statement last month, just days after reports that InBev was considering a bid for Anheuser-Busch.

Adolphus Busch cited Buffett's role earlier this year in helping finance candy maker Mars Inc.'s announced $23 billion buyout of gum industry giant Wm. Wrigley Jr. Co. and said a potential InBev buyout of Anheuser-Busch boils down to shareholders, not family legacy.

"Should Mr. Buffett see this merger as a positive action for all shareholders involved, the likelihood of a deal will increase enormously," Adolphus Busch said.

InBev, based in Leuven, Belgium, made an unsolicited $47.5 billion cash bid for Anheuser-Busch on June 11. The offer represents an 18 percent premium to Anheuser-Busch's all-time high in 2002. The St. Louis brewer hasn't answered InBev yet, except to say it's evaluating the offer.

Buffett hasn't expressed an opinion, either, and there's no indication he will. But an unattributed report in a European newspaper suggests that Buffett backs the InBev bid. And London's The Observer newspaper reported that Buffett planned to meet with August Busch IV.

Spokeswomen for the companies declined to comment on whether the respective boards have had any discussions with Buffett or have any plans to meet. Buffett spokeswoman Jackie Wilson didn't return a call seeking comment.

At 77, Buffett is the world's richest man, with an estimated $62 billion, according to a recent ranking in Forbes magazine. He's considered a guru of value investing and revered for his folksy Midwestern style. Despite his wealth, he has lived in the same Omaha, Neb., home that he bought 50 years ago and pays himself just $100,000 as the chairman and chief executive of Berkshire Hathaway, which he took over in the 1960s.

Today, Berkshire has $44 billion in cash and owns companies across a variety of industries. It is also a major investor in iconic U.S. companies such as Coca-Cola Co., American Express Co. and Wells Fargo & Co. Berkshire's annual shareholder meetings in Omaha regularly draw more than 20,000 people.

Buffett also has been a key player in several big buyouts in recent years.

In 2005, his blessing was key to the $54 billion takeover of razor maker Gillette by Procter & Gamble. He owned about 10 percent of Gillette and had profited handsomely from it over the years, but when P&G came calling, he said it was "a dream deal," and upped his stake in the newly merged company. Since the merger, P&G's share price has grown 24 percent, and Berkshire Hathaway's stake is worth $6.7 billion.

The Gillette deal and his role in the Mars agreement to purchase Wrigley burnished Buffett's reputation as a "brand investor" — one who puts his faith, and his money, in established, well-known companies that sell consumer staples steadily in good times and bad.

While Buffett is famous for investing in businesses for the long term, he has a relatively short history with the St. Louis brewer.

On April 21, 2005, a day after Anheuser-Busch shares had dipped to a three-year low, the brewer issued a brief statement noting that Berkshire Hathaway had become a "significant" shareholder. It didn't mention the exact size of the investment or when shares were acquired.

The purchase seemed like vintage Buffett. Anheuser-Busch was then like it is now: A consumer products giant operating in a mature, slow-growing market. Earnings were in decline, and shares were sagging as Budweiser and Bud Light drinkers increasingly were turning to wine, spirits and craft beers.

Still, it had half the country's beer market and powerful brand names.

Other investors followed Buffett, and Anheuser-Busch shares surged almost 7 percent on the news, its biggest one-day gain since 2001.

But now, those familiar with Buffett and his investment philosophy say it's unlikely that he will play the role of white knight by acquiring more Anheuser-Busch shares, or even helping the company engineer another bid to rival InBev's — two possibilities that some have put forward as possible defenses.

"I would really be surprised if he got involved. In fact, I would be shocked," said Gerald Martin, a visiting finance professor at American University in Washington, who co-authored a recent study on Buffett.

Journalist Roger Lowenstein, author of the 1995 biography, "Buffett: The Making of an American Capitalist," also sees the sage of Omaha staying out of the Anheuser-Busch—InBev scrum.

"I think the most likely role for him is as a sounding board for management," Lowenstein said.

It's not known exactly when Berkshire acquired all of its Anheuser-Busch shares or exactly how much it paid. But assuming the bulk of shares were bought around the time Anheuser-Busch issued the statement in April 2005 — when the stock was at a 30-month low — Buffett and Berkshire stand to make as much as $600 million if InBev's $65-a-share offer is accepted.

"He's not averse to taking a profit if someone offers it," Lowenstein said.

In fact, Buffett's connections aren't limited to Anheuser-Busch. From 1998 to 2003, he served on Gillette's board with Jorge Paolo Lemann, one of InBev's largest shareholders.

Kilpatrick, the author, said the global nature of InBev might make it a more appealing investment to Buffett, who last month embarked on a much-heralded "European shopping trip" and is trying to extend Berkshire Hathaway's reach on the continent.

"The combination (of InBev and A-B) would be more international, and that may be a plus," Kilpatrick said. "It would a huge world company, a brand name, and that's the kind of thing he likes. It would seem to me that this would have some appeal to him."

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