This TEVA / MNTA is pretty interesting. My own guess is that some hedge funds knew yesterday that a letter was coming, and letters are usually bad. Thus a lot of calls were bought yesterday and the early AM spike up. But after reading the letter, it wasn't so bad so they got out of the longs. Or maybe the market is just nuts. I wonder if shorts increased of they covered a bundle today? I would have to guess they covered a bunch.