So you do not now know and just guessing like the rest of us. I think miners are just in it to make money nothing o do with their effort or true believers but I'm also just guessing with that.
In the US you have to pay tax if you sell. Why not hodl? http://theminersunion.com/2017/09/11/what-you-need-to-know-about-bitcoin-mining-taxes/
They are avoiding tax by selling BTC for gold
"We noticed more miners converting to gold on vaultoro instead of fiat. They give bitcoin to another trader and that trader gives them allocated gold. They then trade that gold back for bitcoin when they need to pay bills. Interesting bank independent times."
https://cryptopotato.com/miners-dilemma-sell-mined-tokens-fiat-invest/
