You're right. Any idea who some of the other whales are? I've been doing a bit of research around it but only found Bitmain so far.
Here you go, a medium post from Mar. 1, maybe something has changed in the meantime
“Unknown BCH Mining Wallet #1” — Almost definitely ViaBTC or Antpool, this wallet started mining on BCH’s first day (8/1/2017) and currently controls 0.28% of all BCH with 47,421 BCH. This wallet has also never spent a single coin.
Unknown BCH Mining Wallet #2 — Also, almost definitely ViaBTC or Antpool, this wallet controls the 8th most BCH with 0.52% or 88,855 BCH and also hasn’t spent a single coin.
Unknown Wallet — A newer BCH wallet that isn’t a miner wallet and appears to be some kind of sales wallet. This wallet currently controls 78.5k BCH and, yet again, hasn’t sold a single coin. It’s very possible this is Bitmain’s new wallet to replace #1.
Quoted from: https://medium.com/@btcWolves/bch-heading-towards-the-abyss-f1b2b9ec41f1