In adopting our requirements, we were guided by two public policy objectives-the financial integrity of FDMs and the protection of retail customers who engage in these principal-to-principal transactions. Satisfaction of these two objectives led us to establish security deposit percentages that were approximately in line with the then existing margin requirements for exchange-traded foreign currency futures at the Chicago Mercantile Exchange ("CME"). NFA's security deposit requirements, like the SPAN margin levels set by CME, recognize that currencies can have differing risk and levels of volatility.