The foreign exchange market is a zero sum game in which there are many experienced, well-capitalized professional traders (e.g., working for banks) who can devote their attention full time to trading.

An inexperienced retail trader will have a significant information disadvantage compared to these traders.Retail speculators are almost always undercapitalized, and as such are subject to the problem of Gambler's Ruin. In a fair game (e.g. one with no information advantages) between two players that continues until one trader goes bankrupt, the player with the lower amount of capital has a higher probability of going bankrupt first. Any speculator who plays this strategy (i.e., gambling with no skill at forecasting market direction) is effectively playing against the market as a whole, which has nearly infinite capital, and he will almost certainly go bankrupt. Any speculator—particularly undercapitalized traders who do not have any informational advantages—needs to carefully consider if they can "beat the market" using a profitable strategy.

The retail trader always pays the bid/ask spread, which makes his odds of winning less than those of a fair game. Additional costs may include margin interest, and if a spot position is kept open for more than one day, the trade must be "resettled" each day, each time costing the full bid/ask spread.

According to the Wall Street Journal ("Currency Markets Draw Speculation, Fraud", July 26, 2005), "Even people running the trading shops warn clients against trying to time the market. 'If 15% of day traders are profitable,' says Drew Niv, chief executive of FXCM, 'I'd be surprised.'"