Quote from feisty70:
One way would be if IB #1 internalizing your order, they buy it at 1.00 and sell to you at 1.05, that would say on confirm, IB may have acted in as principal. Also the bad fill could be attributed to the rebate that the IB might get from that market maker that the order went to. How if its volume driver, can some of the smaller firms come close to matching the $7-12 ticket charge, w/o the volume. The fill you get on an order to me is more important than the commission. I should say I dont buy the 5,'s and 10 contracts, I trade the 50's to 100's contracts.