simon - so you dont seem to offer many markets do you like us stocks etc. thats another reason to go dma. eg i can open an account with interactive brokers and trade all the main stock and futures markets in the world, so why should i go for a spread betting firm that will rip me a new a*rs hole at the first opportunity, while charge me interest for the privo?
as for icebergs and order types, i think youre wrong (yet again). why would a sb provide iceberg functionality when they would rather just fill the whole order in 1 fill which is better for both parties? do you know what an iceberg order is and why its used?
as for dealer intervention and stop hunting, here are the facts:
joe goes long at 5, he places his stop at 2.75. the sb algo sells to him at 5, and gladly takes his stop order too. lets say the REAL market is trading at 4.75 - so joe is already at a loss, but thats another story... later on the real market is at 3.25. sb algo is quoting everyone else at 3 bid. but wait! sb algo knows it has a stop on its book at 2.75. there is nothing that says sb has to quote all customers the same price, or x ticks away fron the REAL market. so, while fred sees 3 bid, joe sees 2.75 bid and his stop filled. no human intervention there fellas! yet hang on, the REAL market never even went there.
suddenly price is quoted at 3 again to entice joe to get back in for another bath. if joe does get in, this time with luck on his side (boy does he need it!!). price goes up to 6. fred sees 6 quoted, but joe sees 5.75 as sb computer knows joe is long, so it knows joes next action will be to sell - so why quote him at 6 when it can buy back at a lower price?
thats what happens folks. you can see that such logic isnt hard to code into any software, and the odd tick away from the REAL market can easily be explained as 'spread'. i know because a good friend demoed his firms algo to me - sorry, thats some bloke down the pub to you lot!....
why do you think all sb companies love pushing their 'free education' programs and teach what seems to be a good idea - our friend the stop loss order? what nice guys having such an interest in our financial well being!!
finally simon, as for that report, clearly, as you acknowledge, it wasnt commissioned by any exchange - i thought as much. good of you to admit this. you earn an extra big pair of floppy shoes!