Someone please remind me, in case I missed it, why does this happen on OKCoin?
On huge volume the price barely moves, then on low volume we have this drop (or the previous pump)?
I wish that those totally useless "bitcoin news" sites would investigate and report on this issue, if only by asking the exchange owners about those spikes.
On a couple of occasions, I have seen a huge sell order flash on the OKCoin order book, just at the top of the spread, only to be immediately and precisely eaten by a matching buy order. They may be trades arranged in advance, set to happen at a predetermined price or time.
I seem to recall, several years ago, an announcement by some exchange that they were implementing "shadow" book orders, that are invisible to most ordinary clients. Perhaps they just started showing shadow-book trades on the ordinary ticker, to boost their public volume numbers...
That seems to be what's happening. But why would they want a lot of off book transactions? Don't they make money based on a percentage of the order cost? Why would they not want the price to rise as much as possible?