Not only are USA-only stocks faring much better right now, so is the almighty dollar. In fact, the weakness in the BRIC currencies is the main reason for the BRIC stocks recent decline. Wasn't the U.S. dollar supposed to fall apart and lose its reserve status ? Just saying. I vaguely remember hearing that a few times these last years.
As chaos looms in Europe and the developed economies go straight forward to an economic recession, investors are desperately looking for perceived "safe havens". Slowing market in the BRIC economies is not helping too.
The result ? A huge flow of interests out of the emerging-economies currencies into "safe" currencies such as the U.S. dollar. What investors yanked out of the emerging-markets didn't end up under the mattress. In fact, the U.S. Dollar Index, which measures the greenback against a bunch of 6 currencies, is up for 14 sessions in a row. On the other hand, worst hit have been the Indian rupee and the Brazilian real.
The only currency not to point south has been the Chinese yuan. In order to preserve China's exports, Beijing rigs the currency markets to decrease the exchange value of the yuan versus major economic-partners currencies.
The dollar is not as perfect as we would like it to be, but still as a reserve currency I wouldn't bet against it.