The anti-Martingale, or reverse Martingale, system is a trading methodology that involves halving a bet each time there is a trade loss and doubling it each time there is a gain. This technique is the opposite of the Martingale system, whereby a trader (or gambler) doubles down on a losing bet and halves a winning bet.
Both systems are trading strategies commonly used in the foreign currency markets but can be applied elsewhere. (資料來源)
The original Martingale system was introduced by French mathematician Paul Pierre Levy in the 18th century as a way to maximize the statistical outcome placing a series of risky bets. In a Martingale strategy a gambler or trader doubles his bet each time he loses, and hopes to eventually recover those losses and make a profit with a favorable bet.
On the other hand, the assumption of the anti-Martingale system is that a trader can instead capitalize on a winning streak by doubling his position.The anti-Martingale system accepts greater risks during periods of expansive growth and is considered a better system for traders because it is less risky to increase trade size during a winning streak than during a losing streak. This type of thinking may fall into the “hot hand fallacy” trap, but when markets are trending up, the anti-Martingale system could be successful for a trader, who may pick off a series of positive trades before a loss interrupts his streak. However, a doubling down on a given winning bet exposes him to a single large loss that may wipe out previous gains. (資料來源)