https://www.thinkorswim.ca/tos/myAccounts/displayRates.tos "$9.95 per trade (market or limit orders; 5,000 shares maximum) For orders over 5000 shares, any order types other than market or limit, or extended hours orders the commission for the entire order is our per share rate of $.015 per share ($5.00 minimum)." So it seems that in extended hrs, ToS becomes 3 times as expensive as IBâs 0.005. Not good!. Am I correct? So maybe one strategy to reduce comm would be to use ToS to trade using the flat fee rate of 9.95 for a)highly liquid stocks b)during regular sessions. For other times IB can be the main broker and especially so for illiquid stocks and small share lots.