Ok, here’s what I did, just as a test I told a three percent OTM ES call expiring tomorrow. I was told the margin would be $13,000. When I asked if that was SPAN margin, I was told, after a couple or phone transfers, that they take SPAN And add some Special Schwab risk parameters. Thus, I think, SPAN margin really depends only what the broker will do for you. I wonder what other brokers would request for margin for a similar trade?