Yu Yongding explains:

. . .despite China’s position as one of  the world’s largest creditors, its net investment-income balance is deeply  negative. In fact, China has run investment-account deficits for six of the last  nine years, with preliminary statistics suggesting a deficit of $57.4 billion in 2012.

Two  factors explain this anomaly. The first is the high return on foreign investment  in China. In 2008, US corporations gained a 33% return on their investments in  China, while other multinationals got a 22% return. By contrast, the return on  US government securities, which form the bulk of China’s foreign assets, was  next to nothing.

Second,  China’s foreign assets are denominated almost exclusively in US dollars, while  its foreign liabilities are denominated mostly in renminbi. As a result,  whenever the US dollar declines, China’s net international-investment position  (the difference between its external financial assets and liabilities)  deteriorates – and so does its investment-income balance. China’s drive for  renminbi internationalization so far has made the balance-sheet structure even  more unfavorable.