I can say that in the December the whales withdraw a big amount from crypto market for Christmas . So market getting dump in every December also some coins are in hype because of there launchpad. Other cause may be shifting of money for one to another .
if there's one thing I noticed in this crypto market:
whales and hodl don't sell bitcoin to buy christmas stuff, they have real world money to buy christmas stuff
these guys who make Hodl or whales are making long term investments, they can only sell to buy low, but they don't sell to spend.
Whales are more known to have bundle of money so they can spend as much as they want without touching their cryptos. But for regular hodlers, i think they also plan to have some funds for this holiday season so they will probably sell some of their coins. So its not really surprising that there will be price dumps these days as more people are going to spend than to save. And its always a trend every december, but after this we will still witness price recovery once all these activities will be over.