NEW YORK — It took less than two full days of play for Warren Buffett to win his bet that no entrant in a Quicken Loans contest would predict the winner of each game in the NCAA men’s basketball tournament.

Had someone been successful, his Berkshire Hathaway would have been responsible for paying a $1 billion prize as part of an insurance policy it sold to the lender.

Two upsets – Dayton’s defeat of Ohio State two days ago, and Mercer’s win Friday against Duke – wiped out 99 percent of the entries. When Memphis defeated George Washington Friday night, the last of the perfect brackets was busted.

“While everyone loves an underdog, you could hear a collective groan around the office each time an upset happened,” Jay Farner, president and chief marketing officer of Quicken Loans said in an emailed statement. “We knew that meant a lot of the entrants had their brackets bust, and lost their opportunity at the billion dollars.”

The contest was announced in January and proved a publicity bonanza for Buffett, 83, and Quicken Loans founder Dan Gilbert. Print and broadcast media focusing on sports, business and general news have covered the contest and speculated about the probability of a winner emerging. Both companies declined to say how much the insurance cost.

Calculating the exact odds of a perfect bracket is impossible, because picking the winner of a game isn’t a random event like a coin flip, Buffett said. That’s especially true in the first round when the top-seeded teams almost always prevail.

“I charged a premium that was a reasonable amount above what I thought the odds were,” he told ESPN before the tournament began. “I had another guy at Berkshire Hathaway make his own calculation, independent of me, and we were in the same ballpark. But it was a pretty big ballpark.”