I checked with someone. But he says it's hard to guess. I was afraid he was going to say that. But he agrees that something is definitely wrong and shorting might be involved.
Like, the market makers may know that a supply is coming so they short the stock. When in the background the collateral shares are being sold. I think that was his point.
So you can't really say what is going on based on the information we have.
On the one hand, we didn't see any T-trades. Which points to short selling. OTOH, who in the heck would be shorting that many shares?
News 
Market Data 
Discover 
