You've stated your case? Well, I think it is a very poor case. Your case is the sort of irrationality I would expect to hear from a compusive gambler, or any other sort of addict, when somebody else stops enabling their addictive behavour. I would rather IB require high margins so that it can charge low commissions, instead of requiring low margins, which would stick IB with trading losses by deadbeat gambler-customers, thus requiring higher commisssions. I also find quite ridiculous the notion that IB has somehow committed a felony, by choosing to set futures margin requirements at the levels IB sees fit.