Shorting stocks is tricky so we must give FB praise for taking that side of the trade. If he had well reasoned arguments for shorting, I am sure more people would listen to him but CCL is far from 'overvalued' and his argument appear to be based on his assumptions about the future success of this company. We all know in general how accurate future forecasts tend to be, and this is when they are done by highly educated, well resourced individuals. What is interesting is looking at the short interest on this stock. You could see that going into the announcement last Friday, shorts were loading up and short interest was climbing. The short interest after the announcement is significant lower suggesting a lot of shorts covered and somewhat of a 'short squeeze' occurred which would help to explain why the price has moved up as it has.
The point is, FB was far from alone in thinking the stock would go down further, so whilst there may be plenty of examples of him being wrong in other places, his short position in CCL was actually just a small part of a much wider view on CCL and you cannot hold that against him.
CCL Price at posting:
$9.29 Sentiment: Buy Disclosure: Held