Recently I sold a large number of contracts with a limit price that was equal to the bid. I used IB TraderWorkstation and the order was placed through PSE (routed by SMART). To my surprise, I paid a HUGE penalty which, according to IB, was due to "my limit price being equal to the bid, and consequently subtracting liquidity." Also, IB mentioned that if my limit price were different from the bid, I would be adding liquidity and would not have this problem. Anyone have similar experience?