RE:RE:RE:RE:VolumeYour broker's computer would automatically check and select the exchange for the best bid. Hopefully. Or more likely, if it's a big broker like TD or BMO, they execute/match your trade on their own electronic books. Ever wonder how they can confirm your trade instantly, or within seconds, of you pushing the button? They either instantly match your buy with another client's sell, or they act as "pro" and take the other side of your trade instantly. Let's say you sell 1000 TD bank shares. Your broker would buy them for their own account and simultaneously offer that number of shares for sale if they don't already have another client wanting to buy. 99.9% of the time all the daily trading nets out to very little change in the "house" inventory and they actually make an extra penny or two per share on the bid/ask spread. Okay. Now that's enough. Feels like homework. I hate homework. Gives me a headache and no doubt the newest latest virtual exchanges are even more confusing than this already is. Let's say it's all "magic". Easier to understand.