IB margin calculation really rediculous!

[christianhgross]

Quote from hey825:

for ndx 1425/1475/1500 butterfly charges about $5000/spread on margin. IB is pretty stubbon and has no plan to change this. For the same position, TOS only charges $2500, half of IB amount.

The real question here is how much money do you have in the account?

Because when I tried this out on my account I was charged about 40 USD margin on a single contract. Why so low?

1) Portfolio margin
2) Diversified account
3) Enough money in the account

If you have none of the above IB will charge you full prices because they need to cover their money.