“Strategically, it probably has been China’s intention to find the right time
to lighten up its excessive accumulation of U.S. Treasuries,” he said.
I think that is the crux of it. They are itching to move away from dollar and any excuse to do so is used. This has also been tied with AIIB & they accumulating a large amount of gold to back up their currency to be the base denomination for global trade.
James Rickard's Currency Wars, and The Death of the Dollar are interesting reads. I have given copies to family members because even if Rickard's is not totally correct, his analysis is interesting.
