What you says doesn’t make any sense. First of all this is not the one and not the last stock that is not moving or is going down after approval, it usually happens considering you have no catalysts ahead but just partnership announcement that could hit anyday and second It did approx 70% after approval at $3,81 (before going down again).
That being said, no one is saying this will explode or something similar nor that it will collapse. It will trade up and down until deal is announced.
Play safe and don’t get emotional.
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