AVXL seems to be an exaggerated move of the XBI. Will both move a bit higher briefly in the morning or be met with a large opening dip? Sold some as a trading hedge against the 14% increase.
A bidding war. That will be the start of the new acronym; They Got This! TGT, to be preceded by TWT, They Want This! or They Wish They Had This! TWTHT. Or, Biogens lament: YHTBYBI, You Had This But You Blew It!
They might be letting it run until CTAD, then lowering the boom.
Sailing expression, you could get knocked overboard or worse.
Just a wild uneducated guess.
Or a bidding war starts to purchase the next cutting edge CNS biotech company,