I don't know enough about Chinese politics to be able to reliably comment on their intentions, but buying dollars like this could help push down the price of the Renminbi compared to the Dollar. That has been part of China's economic policy for a long time. Also, when you think about how China is under international pressure to allow the Renminbi to start naturally moving up in value, these types of currency pressures would certainly make a nice way to keep the Renminbi low without having to responsibility for it.