The chart above shows the top ten bitcoin holdings of public mining companies. Some of them own thousands of bitcoins, and six of the ten largest bitcoin treasuries held by public companies are bitcoin miners.
Marathon is the largest holder with 9,673 BTC on their balance sheet, closely followed by Core Scientific, which owns 9,618 BTC. Core Scientific has more than double the hashrate of Marathon, so it should overtake Marathon's position as the top hodler very soon.
Why are the miners so focused on building bitcoin treasuries?