thanks for the answer...
i have IB margin account with less then 110K, how come?
from my 6 months with them i have no complains at all though i wish that part of their service they could block dumb moves that i've done
i still don't get the level thing...
You probably have a Reg T margin account, not a portfolio margin account.
Difference is that in a Reg T margin account the margin is calculated based on each single position, while in portfolio margin account margin is calculated by looking at the overall risk of the portfolio.
Example: You buy a Dez 180 call today, you sell a 190 call tomorrow. In reg T account you need more margin for selling the call than in a portfolio margin account, since portfolio margin sees that you already have a 180 call, so the risk is only 10, not 190.
Also in portfolio margin acct margin requirement for buying stock is only 15%.