means, the biggest bitcoin holder is US government?
No, Satoshi Nakamoto remains the largest bitcoin holder, holding over a million. And of the states, the small European country of Bulgaria has 213,519 bitcoins, so from what we know from open sources, it has the most bitcoins after Satoshi Nakamoto.

We never know if Satoshi will be back or not. He might not be back! Even if he is alive, he might not move it for a long time and his address will remain dormant. BTW, I didn't know about Bulgaris's holding.