Happy Valley Racecourse in Hong Kong. 

Happy Valley Racecourse in Hong Kong. 

Photographer: Xyza Bacani for Bloomberg Businessweek

The Gambler Who Cracked the Horse-Racing Code

Bill Benter did the impossible: He wrote an algorithm that couldn’t lose at the track. Close to a billion dollars later, he tells his story for the first time.

Horse racing is something like a religion in Hong Kong, whose citizens bet more than anyone else on Earth. Their cathedral is Happy Valley Racecourse, whose grassy oval track and floodlit stands are ringed at night by one of the sport’s grandest views: neon skyscrapers and neat stacks of high-rises, a constellation of illuminated windows, and beyond them, lush hills silhouetted in darkness.

On the evening of Nov. 6, 2001, all of Hong Kong was talking about the biggest jackpot the city had ever seen: at least HK$100 million (then about $13 million) for the winner of a single bet called the Triple Trio. The wager is a little like a trifecta of trifectas; it requires players to predict the top three horses, in any order, in three different heats. More than 10 million combinations are possible. When no one picks correctly, the prize money rolls over to the next set of races. That balmy November night, the pot had gone unclaimed six times over. About a million people placed a bet—equivalent to 1 in 7 city residents.