"The recent liquidity crunch, and its cause, illustrates some of the difficulties China's economy will face in the future. Over the last two years, and especially in 2013, mainland corporations with offshore affiliates had been borrowing money abroad, faking trade invoices to import the money disguised as export revenues, and profitably relending it as Chinese yuan. As China receives more dollars from exports and foreign investment than it spends on imports and Chinese investment abroad, the People's Bank of China, the central bank, is forced to buy those excess dollars to maintain the value of the yuan. It does this by borrowing yuan in the domestic markets. But because its borrowing cost is greater than the return it receives when it invests those dollars in low-earning U.S. Treasury bonds, the central bank loses money as its reserves expand. Large companies bringing money into the mainland also force the central bank to expand the domestic money supply when it purchases the inflows, expanding the amount of credit in the system."
This is proven true [I am sure it is true... else, Pettis wouldnt be writing about it] affects a lot more than just Chinese problems. It questions the integrity of China's trade numbers, data points that we receive and such. But then, alas, they have always been in question when it came to China.