Many blame America’s shadow banking system, where dangers lurked away from the scrutiny of complacent regulators, for the massive financial crisis of 2008-2009. Richard Fisher, president of the Federal Reserve Bank of Dallas, said in a speech on Thursday that he is now worried about the risks to China from its own version of the shadow banks.

During the recent credit boom fueled by the 4-trillion-yuan fiscal stimulus, off-balance-sheet lending by banks and private loans by nonbanks exploded. This shadow-banking lending activity accounted for an estimated 20 percent of China’s total loans in 2011. With the cooling of the real estate market and with slower economic growth likely in the near term, a large share of these loans could turn bad. And because these loans took place outside the view of regulators, the effect of a sudden disruption in repayment is virtually impossible to predict.

Fisher was highlighting this concern to suggest that, while China’s efforts to reform its currency system are welcome, the authorities must be careful not to open the country up to volatile capital flows at a time when the world financial system is already very fragile:

On the international front, the sovereign debt crisis in the euro zone has resulted in much uncertainty and volatility in global financial markets. Should there be, say, a sudden and messy change in the participants in the economic and monetary union, a chain reaction might ensue that could result in some unpleasant responses. Just two weekends ago, for example, the Swiss National Bank warned that it is considering capital controls on foreign deposits if Greece leaves the euro zone. Clearly, any policy shifts affecting China’s