The Martingale system has you double your bet after every loss, so that the first win would recover all previous losses plus a profit equal to the original bet. For example, say you started with a $100 bet and lose. You would then double your bet and continue doubling each bet until you finally win ($100, $200, and so on.). By the time you reach your fifth bet, you’d be risking $1,600. The Martingale betting strategy is seen as a sure thing by some since a gambler with an unlimited bankroll will eventually win.