Paddy Power, the Irish bookmaker, has paid out on all bets that Barack Obama will win the US presidental election a day early, claiming that Obama is "a nailed-on certainty" to win a second term.

The move is part publicity stunt, part business move, and part a betting company taking a bet on the election – to the stake of $650,000, according to a press release from Paddy Power.

The publicity stunt aspect is pretty obvious – you're reading this story, after all – but the business move is slightly more interesting. Paddy Power, as with any betting company which pays out early, hopes punters will re-invest their winnings in a more uncertain bet on the election. The bookmaker is pushing the idea that the margin of victory is a fun bet to take part in, and it's certainly one where you could win more money: the odds of an Obama victory bottomed out at just 2/9, while if you follow Jim Cramer's prediction of a gigantic Obama victory, you could get 25/1.

And as for the bet on the election – well, Paddy Power will be pretty annoyed if they've called it wrong and have to pay out on Romney as well.