4.2.1.3.1. Exercise and Assignment
Remember that options trading follows American-style rules and can be exercised at any time. To exercise an option, the buyer must notify his broker or futures commission merchant, who in turn must relay the notice to the proper clearinghouse. The OCC or DCO must respond by not only closing that position but also cancelling the pre-existing position of an option writer. The cancellation is called assignment, and the writer is said to be assigned the
