Billions according to the API of a super untrustworthy exchange who's been known to aggressively wash trade.
The data aggregators list UpBit as one of the least trustworthy sources of information.
It's still undeniable how many coins the exchange itself holds.

Honestly there's a lot of evidence to suggest that the biggest pump from last cycle came from exploiting Splinterlands with bots. These bots were spending 3 Hive to create an account and then paying $10 to farm Splinterlands rewards. It's not a coincidence that the cost of 3 Hive just so happened to peak around $10.