IB doesn't look at the overall picture of how your account would stand by taking into account all of your positions. No, it only looks at each individual position and as soon as it sees any one position would pose any potential counterparty risk to IB, it takes it out. It doesn't care that you actually have other positions that will offset it or will cover it. It performs some kind of "stress test" on your account and the algorithm is proprietary. It's a POS. I receive shit messages all the time telling me my margin is below the threshold when all of my positions are covered by cash and I am not using any margins cuz I trade small. And other times it's because they didn't release my funds in time after the options that I have traded have already expired. IB is shit in those aspects. I don't even bother to compose a ticket to report those shit.