In the forex market, an excess margin deposit may arise due to a currency trade returning to profitability after the trader has pumped in additional margin because of an earlier margin deficiency. It can also arise through a currency trade becoming significantly profitable shortly after initiation.
Traders may withdraw excess margin deposits if they reach a significant level, since excess capital in margin accounts pays little or no interest. However, nominal amounts of excess margin deposits may be left in the trading account as a cushion against margin calls triggered by adverse price movements.