This refers to a betting strategy where a gambler increases or decreases the size of his bet depending on whether he won or lost his previous bet. After winning a bet, the gambler doubles the size of his next bet, but after suffering a loss, he halves the size of his next bet. It is believed that the anti-martingale strategy can help maximise the size of gains when a player is performing well in a game of chance, while minimising losses when the same player is faring quite poorly. It has been used by many successful traders to make decisions regarding how much money to bet on a particular trading position.