Hmmmm. Just maybe it might be because they have stock options that expire in mid February and they either need to exercise them or loose them? What are the chances?
That doesn't mean you should or should not sell your long position - that's something you have to decide and should be a decision based on what you think the fundamentals of the stock are. My bet is that you will be able to buy this stock at a lower price down the road, but that's my opinion based on my own analysis. You need to determine what you think is the right thing to do for good sound reasons and then execute your plan!