(ABC News) -- You had to be in it to win it, but far more than 83 percent of participants in Warren Buffett’s NCAA Tournament bracket challenge aren't even in it for the $1 billion grand prize anymore -- having been knocked out by a single game on the tournament's first full day.
Even the 16.1 percent of 8.7 million entrants who correctly picked Dayton to upset Ohio State Thursday weren't in the clear -- because any other wrong pick on the tournament's first day would have wrecked their chance at a perfect bracket right out of the gate.
Yahoo and Quicken Loans, which are affiliated with Buffett's challenge, could not be reached for comment on exactly how many people remain in the running for Buffet’s billion.
But if the results from ESPN’s Tournament Challenge after Thursday are any guide, the odds are not looking good. Over at ESPN, only 18,741 of 11.01 million people (or 0.17 percent) got all 16 games right on the tournament’s first day, ESPN’s Kevin Ota told ABC News.
Looks like Buffett will get to keep his money another year. But then, the finance guru probably worked that out before he backed the Quicken Loans’ challenge in January. As ABC News previously reported, the odds of guessing a perfect bracket was estimated by one mathematician to be 1 in 128 billion (and that’s if you know something about basketball). In the same YouTube video, DePaul University's Jeff Bergen explained that there are more than 9 quintillion ways to fill in a bracket.
There are still at least 50 people left in the running with perfect picks, according to the Quicken Loans bracket challenge website. And if any of those people maintain their perfect score over the next 67 games, $1 billion could be all theirs, doled out in 40 annual installments of $25 million, or a single lump-sum payment of $500 million.
The only other heartening news is that 20 people will be eligible to receive Quicken Loans' $100,000 runner-up prizes for picking the tournament's top 20 most accurate "imperfect brackets."