Oanda accounts for more than half the overall increase.

Despite the recent slowdown in trading volumes, US regulated FX brokers continue to experience growth in client assets held. The CFTC's just-released numbers for March 2012 show a 3% increase in total client assets held at FX firms to $781 million, with Oanda accounting for nearly two-thirds of the increase.

The only firms showing a decrease in client assets during the month were GFT and TradeStation.

For more on the global Forex industry see the LeapRate-Dow Jones Forex Industry Report.