While this is just speculation based on blockchain analysis, that big one was more likely made by a supporter who wants to buy it cheaper from the several smaller bounty dumps. He failed to scare the holders into selling so much cheaper it seems but still managed to reduce the price of smaller amounts for now at least.
Whenever I have free
BTC, I usually wait for dumps from bounty hunters, because during those dumps from greedy bounty hunters, price falls fastly to very cheap one.
Bounty hunters often create dramatical discounts on markets.
And, recoveries from those dumps are so fast.
It's the way to get cheap coins, and quick profits.