There is an excellent article on Chinese news site china.org.cn which points out:
What is not generally realised is that China passed a decisive financial landmark this year when it overtook the US as the world’s largest generator of finance available for investment. As China has overturned a lead that the US has enjoyed for a century and a half, this may be termed, without exaggeration, a turning point in world financial history.
It goes on to argue:
Total US savings, at annualised rates, have fallen from their peak of $2.2 trillion dollars in the third quarter of 2006 to $1.4 trillion. Expressed as a percentage of GDP the drop is from 16.2 percent to 10.2 percent. The latter figure is the lowest since 1934. US savings have therefore fallen to levels last seen in the midst of the Great Depression.
The savings and investment rates are crucial for any real understanding of economic processes. That investment in the US is so low, and in China much higher – partly because of its high proportion of state ownership – will become even more important as the US economy continues to fail to overcome its structural weaknesses.