The odds of Buffett having to pay out reach about 1 in 10,000 in the Quicken Loans contest if all 10 million entrants have basketball knowledge, Bergen said.

Buffett’s Wager

“He’s risking a large amount of money, but in terms of his expected loss, he’s not risking a whole lot,” Bergen said by phone. “Warren Buffett isn’t where Warren Buffett is by coming up with stupid ideas, stupid wagers.”

The NCAA men’s basketball tournament, known as “March Madness,” is among the most-watched sporting events in the U.S. The championship game last year attracted 23.4 million viewers, CBS Corp. said in April after the University of Louisville defeated the University of Michigan. CBS and Time Warner Inc.’s Turner Broadcasting agreed in 2010 to a $10.8 billion, 14-year contract for broadcast, Internet and wireless rights to the tournament.

Trying to predict the winners of each game has become a fixation in the U.S., where colleagues often bet in office pools and compete against celebrities who post their picks online. President Barack Obama has made a public show of releasing his bracket, including in 2009 when he correctly selected the University of North Carolina to win.

Berkshire Assets

Buffett, the world’s fourth-richest person, built Berkshire into a business with operations spanning the insurance, transportation, energy, retail and manufacturing industries. The company had more than $170 billion of stocks, bonds and cash at the end of September, allowing Buffett and his deputies to write policies that protect against the costliest natural disasters and other major risks.

If the insurance industry were to face a mega-catastrophe with $250 billion in losses -- about triple the costliest event ever -- Berkshire would still probably post a “significant profit” for the year because of its many sources of earnings, Buffett wrote in a letter to shareholders last year.

“Millions of people play brackets every March, so why not take a shot at becoming $1 billion richer for doing so,” the billionaire Berkshire CEO said in the statement. “While there is no simple path to success, it sure doesn’t get much easier than filling out a bracket online.”

Of the 8.15 million brackets submitted to ESPN last year, none were perfect after the field was narrowed to 32 teams. The best record, shared by 5 brackets, was 30 and 2.