I feel like such a noob asking this question but I want to know who is right. Isn't a Stop Loss triggered when the MARKET trades at the stop price? I was long 4 BK Dec 35's @ .75 when they gapped up Monday. Sold half the position on Monday and protected the other 2 with a Stop/Limit @ $4.40/$4.40 My position sold at the open today at $4.40. I checked the bid/ask which was at $4.50 X $4.70 with good size. (I wouldn't have used a stop loss for an option if the liquidity wasn't there) My 2 contracts made up 100% of today's daily volume in the Dec 35's. How is that possible? How was my stop triggered? Called Scottrade, he said when my order was executed the BID was $4.30. Can a BID alone trigger a stop? PS: The Dec 35's closed at $4.30 X $4.50 so no harm done but I am curious all the same.