When a call option is exercised, it is said, then, to have been called. For an option on a physical asset, the call writer is under obligation to deliver the underlying once the option is called. In case the option was written on a futures contract, the writer should create a futures position, and therefore, open a margin account. However, if the call writer has already an offsetting position, there will be no need for him to create that position.
December 16, 2024
