US is China's largest trading partner. Every year, US is running deficit of $300-400B.
Foreign Trade - U.S. Trade with China (census.gov)
Since, the trade is in US$, China needs to park its gain somewhere. China can convert US$ to RMB but that it would drive up the RMB and undermine China's competitiveness. It's convenient way to park it's asset. If I am not wrong, China did try on Euros. Certainly, not ₽.
Unless, China and US choose not to trade, this is going to be an ongoing thing.
Foreign Trade - U.S. Trade with China (census.gov)
Since, the trade is in US$, China needs to park its gain somewhere. China can convert US$ to RMB but that it would drive up the RMB and undermine China's competitiveness. It's convenient way to park it's asset. If I am not wrong, China did try on Euros. Certainly, not ₽.
Unless, China and US choose not to trade, this is going to be an ongoing thing.