Yes, slippage. When you trade a spread, someone takes the other side of the trade. That person is not going to give you 15-20 cents when the stock is unchanged. IMHO TOS is a great broker. But, I believe they give you 'fills' in paper trading accounts that are unavailable in the real world. Why do that? To give you confidence and get you to enter real orders. Just a guess. Mark
I'd say simulating a real market fill is...well, impossible...so they have to go by something. In any case, I've said it twice already and I'll say it again, until you test out a strategy in real world live trading it's all guesswork. That's why we are all billionaires on paper!
Good point. It wouldn't make sense for a broker to err on the side of pessimism when creating algorithms for their simulators, would it? Something to keep in mind.
100 is not what i would call a large order. ON the other hand the NBBO should be good for 50 lots so why not start there?