When you do a vertical spread the brokerage keeps margin to cover all of the potential risk. At expiration a loosing position trades stock with a value substantially in excess of the margin. Do you actually need to have funds in the account for that trade? Are there any brokerages that would let me invest 90% of my account if I wanted to and not have reserves to perform that expiration trade? What happens if I do that and loose? Do I get a phone call asking for more money? Has anyone tried…