It wasn't dude. I'll explain anyway since I annotated the chart:
The pink ellipse is where the stock was trading after the news about their negative culture came to a head. The purple rectangle is where it's traded since the news of the acquisition. People will have sold since it's been in the purple square for the following reasons:
- You bought in the pink ellipse (this is the obvious one).
- You bought prior to the pink ellipse and the drop spooked you - you're happy to get out at break-even or at a smaller loss than it would have been if not for the news of the acquisition.
- And/or you think there's a risk the deal wont go through so now is a good time to get out.
- You're a market maker who sells options on ATVI - you need to buy and sell shares of the stock to hedge accordingly.
- You're a hedge fund with a target rate of return for your clients. As you can see, since the news broke the stock has predominantly traded sideways (and will continue to do so for a few more months) - they will have identified places where that money could be better deployed elsewhere in the meantime so will sell a portion (if not all) of their holdings in the stock
Those are the main reasons. The volume indicates that most of the people who intended to get out did so on the day the acquisition was announced (between the prices of 86.90 and 81.5). Nothing will really happen with this stock until the deal is announced on way or another. Any trading that's happening now is people positioning themselves for the next major move, or options market makers hedging.
It's also worth noting that the reason the Bloomberg article came out today is because yesterday the stock fell below the channel it's been trading in since news of the acquisition. That usually (but not always) indicates a move to the downside is coming. 77.70 was the line in the sand, now people are asking why that's happening.