I have accounts at both IB and TOS. I have always used IB for my active trading because of the low commissions. Lately on a few ocasiina i have had spread orders that were not filling at IB. Just for fun i would put the same order in on TOS and it filled instantly while my IB order still sat there. I can understand this happening once as a fluke but i have now done it 3 times in the last month. I have seen on here where IB denies internalizing their orders however i have seen other reviews sayimg they do. I like the TOS platdoem better bit stay away from using it because of commissions. But having seen the order fills, the extra TOS commissions are nullified if i am consistently getting better fills. Can anyone provide insight on this issue and whether or not IB internalizes the smart routed and does not place them on the exchange?