I had a similar issue with IB when trading ES. They replied it is on purpose to discourage people from trading certain months where they felt there was low OI. I tried to explain that ES had the highest OI of any futures product but they wouldn't listen. If IB doesn't want people to trade certain products then don't offer them. https://www.elitetrader.com/et/thre...-ib-margin-calculator-and-support-are.306919/ I have started trading ratio spreads on oil, I like it.