I think it's anticipation of further merger activity in the biotechs. Note that most of the attractive merger candidates are up considerably today. It is great, though, to see this kind of break out for IMGN so there may also be something company specific brewing.
sounds about right. Sold some calls here, probably helping to fuel the rally. Very unexpected on decent volume, must be an upgrade, or some news only known to institutions. DJ just sold some shares, so apparently he was not aware either. Nice to see a break out! Now I can spend more time on my day job and stop complaining until the offering or the good thing that is unknown is announced. WOW, major break out!