This merger has been on the books for a while now. Activision already approved the acquisition at $95/share in April. Since then the stock is 22% below that price point.
The FTC has stepped in and is asking for more information and data as to how the merger could effect the other competition in the space.
The reason that ATVI stock is somewhat attractive right now is because buyers could make upwards of 30% in over a year. This figure came from the 30% upside from the merger arbitrage, and that alone is something attractive given the market volatility. Microsoft has the money, and the deal would have pushback from regulatory practices, and the deal is still moving forward.