I am looking at the Interactive Brokers Time and Sales stream for the June emini S&P at 09:12:01 Chicago Time today 6/2/2011. I was long the emini and had a MIT sell at 1316.50. When the market traded at 1316.50 I was not filled. The IB representative explained to me that although there were many trades in the "Last" column at 1316.50 I was not filled because there were no bids. My question is a)How do trades occur with no bids at that price and b) Is there a better method to guarantee a timely fill when the "last" price hits my trigger price? In this case the bids are 2 ticks below the "last" for quite a few trades. I have always been filled promptly on this kind of order before, assuming I take a tick or so slippage, so I am confused about what happened today. Any traders or IB folks who could clarify?