JonAgi

I would like to know why if i buy an option contract of US500 for example, and i sell option on US 500 and form a bull call spread; Instead i get margined by IG on both legs(long and short legs). Also i even tried tried to buy one option and sell another on option on the same contract, expiry, strike and type(using force open) now my exposure is supposed to be net zero but on IG i am not only margined on one leg but instead margined on both legs of the trades. Lastly, i think same thing holds when i try to hold both short and long positions in the underlying US 500 contract.

Is there no reduction in margin on IG for holding long and short contracts simultaneously in the underlying or options trades ?

I would like to know why if i buy an option contract of US500 for example, and i sell option on US 500 and form a bull call spread; Instead i get margined by IG on both legs(long and short legs). Also i even tried tried to buy one option and sell another on option on the same contract, expiry, strike and type(using force open) now my exposure is supposed to be net zero but on IG i am not only margined on one leg but instead margined on both legs of the trades. Lastly, i think same thing holds when i try to hold both short and long positions in the underlying US 500 contract. I am new to using IG, someone should please explain to me why it is so? And is all IG contracts margined like this one with no margin reduction? Thanks.