Before revision:  Here we investigate the collective dynamics of the international currency exchange market and show the existence of a semi-invariant signature  masked by the high degree of heterogeneity in this complex system. The cumulative fluctuation distribution in the exchange rates of different currencies possess heavy tails characterized by exponents varying around a median value of 2. The systematic deviation of individual currencies from this putative universal form (the "inverse square law" ) can be partly ascribed to the differences in their economic prosperity and diversity of export products.
After revision:  Here we investigate the collective dynamics of the international currency exchange market and show the existence of a semi-invariant signature masked by the heterogeneity in the properties of the components comprising such systems, we consider the exchange rate dynamics in the international currency market. We show that the exponents characterizing the heavy tails of fluctuation distributions for different currencies systematically diverge from a putative universal form (the "inverse square law" ) can be partly ascribed to the differences in their economic prosperity and diversity of export products.