Simply, most Asian country's have high savings ratios, where as countries such as America have high consumption ratios. Therefor you have Asian countries being exporters of Capital and America being importers. For the asian countries with a floating exchange rates is pretty much forces them into being exporters of G & S as well in order to keep the Balance of payments balanced. The only except is China (who's a net importer of capital and net exporter), but this is due to them fixing their exchange rate, which some estimate to be about 50% undervalued. What do they do with all this money flooding into their country? Buy US government bonds and pretty much hold them ransom. They will have to float their exchange rate eventually, there is only so long before the government can no longer steralize the huge inflow of money into their economy. Sorry been studying economics for a few days