Large miners sell their BTC because they have to pay the bills in USD.
I see this said a lot. Is there any basis for it?
What USD bills do large Chinese miners have to pay?
Fine then CNY. The point is they pay bills in fiat not BTC.
As for what bills they pay that should be obvious. Companies producing Asics sink millions of fiat into development and production costs to pay whatever foundry produces the chips. Individual miners buy them in fiat most of the time as well. And of course there is always electricity. I've not heard of a single electric company taking payments in BTC yet. Not to mention rent payments wherever they're leasing warehouse space and of course internet costs. All of that paid in fiat not BTC.