I use MB trading. I also have a firewall at work and can only set orders before the market open at home. Unfortunately, there is no way to do this with market orders through MB. I can only use limit orders. I have a longer term holding period so a few cents doesn't really concern me. SO if at stock were trading at 20 with a few cents sread and I put in a limit buy order for say 30. I pick 30 so I know I'll get filled. My question is will I be hit at 30 or will I likely get filled similar to if I had entered a market order?
If you're talking about NYSE/AMEX stocks, and you route the order to NYSE/AMEX*, you'll get filled at the opening print**. If you're talking about Naz stocks, it's more complicated and depends on exactly what MBT has for Naz LOO/MOO support. You really need to ask MBT. *Via SDOT, ISI, or whatever they use - ask them * Provided your buy limit is at or above that price, or your sell-short limit is at or below that price and qualifies as an uptick or the stock is uptick-exempt.