Quote from jjs235:
Feel free to call them and ask for your own arrangement, but here is what I have been told.
First off, they clear through separate entities like Goldman and Penson. Due to these relationships a minimum account of $500,000 is usually needed. However, the key number is how many shares you trade a day. Currently for them to profit enough off of your account the number is roughly 250,000 shares per day. If you are quickly approaching this number you may still be okay.
Could you trade forex through them? Do they provide leverage? What is their leverage if present? I have an algo that could trade huge number " 10000-20000" of trades per day so what is the minimum trade size for them?.