London-based Betfair was founded in 2000 and has built a huge base thanks to the popularity of horse racing in the United Kingdom. Betfair was set up as a betting exchange, sort of like eBay, where sellers and buyers do their own deals.
Gamblers make their own wagers, as one player sets the odds and the other accepts them. Money is held in escrow accounts by Betfair. When the race is held, the loser pays the winner, and Betfair takes its share of the winnings.
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