The Economist on Hot Money and the Dramatic Growth in China's FX Reserves

Massive hot-money inflows present two dangers to China’s economy. One is that capital could suddenly flow out, as it did from other East Asian countries during the financial crisis a decade ago and Vietnam this year. China’s economy is protected by its current-account surplus and vast reserves, but its banking system would be hurt by an abrupt withdrawal.

A more immediate concern is that capital inflows will fuel inflation. The more foreign capital that flows in, the more dollars the central bank must buy to hold down the yuan, which, in effect, means printing money.