From what I know I think Bitcoin price is always pump by whales or investors and I think the current bullrun might be cause as a result of more investor trying to invest in bitcoin!!!
Whales does not pump bitcoin always, in fact there are only few scenario where we see bitcoin pump compared to dump, but I'm glad we have survive and now this pump bring bitcoin to its ATH. Now, if you'll ask me what's next, I think dump is inevitable.
I have always considered it more about the whales impact and not direct. I think when whales sell or buy that doesn't change the price all that much itself, but when they do it and others see or hear about it the impact becomes bigger. If a whale ends up buying 1 billion dollars worth of bitcoin OTC from some other one, the price will not change, it all depends on how much the market and public knows about it.
If public knows about all the big deals, they will definitely make a big case out of it and change the price as well, but when public is unaware of what is going on, they are not going to react and price will be stuck the same. It doesn't matter how much money is moving, it could be a billion dollars, it could be 100 million dollars it all depends on how much public knows. You could buy 1 billion dollars secretly without moving the price at all, or you could buy 100 million dollars worth and make it public and make the price increase.