As of March 2014, no one has ever come close to filling out a perfect NCAA bracket. In 2010, a 17-year-old autistic boy reportedly had all 48 games correct heading into the Sweet 16, though this claim has been met with lots of skepticism.
A DePaul University math professor calculated the odds of filling out a perfect bracket at one in 9.2 quintillion, though he stated that someone with significant knowledge of college basketball could improve their odds to one in 128 billion. Prior to the 2014 event, Warren Buffet made a public offering of $1 billion to anyone correctly picking all 63 games of the tournament. None of the millions of entrants even had a perfect bracket by the end of the event's second full day.