Why are they trading at less than heads minus strike price? Because it can take a couple of days to convert. If you had bought IBXOA at 11.5 yesterday when IBX was trading at 15.5 it seems like easy money, but there's always the chance of a pullback happening before your conversion goes through and you can sell the heads.
They don't trade lower because of the larger long term risk... That's why they exist, and why they usually trade higher than heads minus strike price!!!
IBX Price at posting:
13.5¢ Sentiment: Buy Disclosure: Held
