Because with most deals at most firms you are really trading your own money while being given leverage. You are usually stopped from trading when near the end of your money. Want to keep trading? Hand the firm more money. Most traders lose their ass, even "trained" (lol) prop traders with so called professional firms.
I keep coming back to ET as I think i finally figured out my ATM.. Is there a canadian firm I could join? happy to shaw my IB account and I am paying way too much....