Actually FNM was down much more than a dollar Wednesday - more like $5. So we're talking almost a 12% drop.
Now, I noticed it IS up in pre-market right now, but only by about 99 cents, which is nowhere near the correction needed to call it an uptrend.
Considering its 50-day MA is at about $52, and today it is opening at close to $42.70, it already is the "tanking" category, IMO.
If it drops to $40, I think it is an excellent candidate to short. Some people are talking about this news with the word 'Enron' in the same sentence.