most firms won't let you place an all or none on 100 shares. as long as it's executed on the same day, you should only be paying one fee. also, you can get executed in odd lots even for all or none, as long as the order is executed completely that condition is satisfied.
From what I remember you get filled on the last print. So if I was scummy, I could monitor a universe of thinly traded stocks. Say the last print on ABC Corp was 31.42 which was a minute ago. Since then the market has rallied a bit and the current mkt on ABC is 31.58 - 31.62. I now have my automated bing bonger program send 100 orders to the NYSE to buy 99 shares at the mkt. I get filled @ 31.42. I now go whack a bid on an ecn and sell 9,900 shares at somewhere around 31.58. This is what pisses people off, and it's understandable.
Most brokers will charge one fee per day. Moreover, AONs have another issue. They are not natively supported by most exchanges so you get a simulated order vs a limit order in the book. This lowers your priority, and also means the order is not a protected order under NMS.
Thanks. I did go back and check and yep, I was charged just one commission. But that leave me unsure of why people so dislike odd lots??? Thanks for the tip about all or nothing. I'll stop using that. Kris
Bec odd lot quotes are not displayed, not protected, more expensive to execute on ECNs.... hedging strategies with options cover round lot multiples.. so if you put in an order to buy 500 shares and get 38 shares, it's a big nuisance. What the hell do you do with the 38 shares? Now you try to get the other 462.... well your quote for 400 will display but not for the 62.... etc. It's true that due to certain outdated practices, odd lots can actually get preferential execution on NYSE, AMEX... but that benefit is small bec the order size is small (unless you abuse the system by putting in multiple odd lot orders, which is what the rules are meant to prevent).