nlightn...Was hoping one of the others would tackle your question. I am fairly new to the options game and am not sure of the answer. I've had it happen a couple of times and even this month with another stock. However, it didn't happen until today. The others also happened at or near the end of the month. This leads me to think it may be related to the timing left on the options. As time erodes, so does the premium. That just might be the case. If I find out any other reason, I'll be sure to pass it on.
G' day Mate,
Aussie
Australia is a beautiful place with wonderful people that just love Americans. You've got to go there some day. Give it a go Mate.