I think it is all about fork. Investors are not sure when and what will happen - the true is that these are only speculations, and in my opinion someone is just playing here. People reactions we can see on charts, but nobody said that fork will ever happen.
I'm sure after the weekend everything calms down.
Speculation or not, investors that aren't really into Bitcoin and just stick to trading, are most likely the ones that are pulling out right now. I can't really blame them as uncertainties regarding everything related to BU grows. Especially now exchanges have released their approach on how to deal with 2 different chains, where both Bitcoin and BU might get a separate exchange listing. Basically the same as what happened with ETH and ETHC. I however don't think it will come that far.