Quote from noddyboy:
They dump treasuries to save their economy as you said.
1) They get the dollars and buy yuan. yuan rises, doesn't save their economy.
2) They get the dollars and buy oil and give people free oil. Then oil prices rise.
In either case, they didn't get the treasuries for free. They sold yuan debt to get it. The yuan debt is worth more than the dollar debt, so the world will suddenly realize that China is not so debt-free after all.
They can't really buy yuan since it doesn't freely trade. I guess they can use the money to buy back debt dominated in yuan. I am not sure who owns the yuan denominated debt or if it is even purchased outside of China.
They can't buy the Euro because it is going down the tubes. No advantage to buying commodities, oil because that just drives up their cost of manufacturing.
Their best route is to keep putting money into treasuries to support the dollar. A strong dollar is in their best interest since most all of their production ends up being in one huge supply chain ending up in the US.
If they do anything to hurt the US economy then they are the ones that will take beating and in China, unlike western democracies, their is no real system there. Its ran like a criminal organization. No laws. If their economy collapses then they will be ripe for a change in government and then the ones in power could lose everything.