Would you know if E*Trade or TD sell order books to HFTs? That is something we debated briefly on my previous post
This is what I am trying to figure out - computing the total profitability of ones account seems to be a dark art. What is considered "real size" in the market these days?
please excuse my ignorance but how do you "borrow and withdraw"? As I thought it only auto borrows when you buy/short stock. I am unaware of a way to borrow without buying/shorting stock
They absolutely sell order flow on regular retail clients. I'm not sure about their active traders though. Usually the advanced platforms can customize routing, exchanges, etc. IB does NOT sell order flow.
It's a bit of a semantics thing. Imagine you have $100,000. You want to buy $100,000 of IBM stock and put down $50,000 as a downpayment on a home. There are a couple of paths to accomplish this, both of which have exactly the same end result. 1. You put $50K in a brokerage account, but $100K worth of IBM on margin, and put your other $50K into your house transaction. 2. You put $100K in your brokerage account, buy $100K worth of IBM, then "withdraw" $50K from your brokerage account, which effectively margins your brokerage account the same as option 1, and then put the $50K into your house transaction. Given that option 2 is functionally equivalent to option 1, it may be a bit confusing to call it "borrowing and withdrawing" even though that is an accurate description of what's going on, it's really just increasing the amount of margin in use on your account.