China is looking to diversify it's foreign reserves, which is currently mostly in US treasury bonds, and will create one of the world's largest investment funds in order to diversify it's holdings with riskier assets.
Fundamentally, this seems like a good idea. There's no reason for a country, which theoretically should be a longer term investor than most individuals to only buy treasuries. As a gigantic investor with no short-term requirements, they should be able to achieve substantial returns, similar to what many Universities have done with their endowments, except an order of magnitude larger.
There may be a message in this for America as well: we won't finance you forever. China is not, of course, the only purchaser of US treasuries, but it is a large on. What would be more significant is if China were to dump the treasuries it currently holds, sending the price down and putting pressure on the US to raise interest rates. According to the article, China is more likely to shift its purchases rather than getting rid of the assets it already has.
This is actually what I thought the US should have done with Social Security. There's no reason diversifying the trust fund has to include private accounts; why not just create a giant social security endowment and invest in a range of assets. I guess this is another instance of an authoritarian government being able to push through policies that in a democratic one get bogged down with all sorts of interest groups trying to make the system more favorable to themselves.