Exercise style is contract-specific

European-style options permit exercise at the prescribed expiry; American-style options can permit it earlier. Both styles exist in the wider index-options market. Check the exchange specification and broker policy rather than extending a rule from one familiar product to every other index.

Assignment does not necessarily deliver shares

For a cash-settled index option, assignment concerns the cash settlement obligation. A short call or put can require a substantial payment. There is no basket of component shares to receive as a consolation for a losing short put. The economic exposure differs from a stock or ETF option assigned into shares.

Automatic procedures and instructions

Exchanges, clearing arrangements and brokers define exercise procedures and deadlines. A contract that has intrinsic value can be subject to automatic handling, and broker instruction cutoffs may be earlier than exchange deadlines. Do not assume an option will simply disappear because it was not actively managed on its final day.

Manage the whole position

Closing one leg of a spread can leave the remaining option exposed. Mixing an ETF hedge with an index option also introduces differences in scale, basis and settlement. Plan the exit and cash requirement before entering the position; a maximum-loss number is not a complete operational plan.

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Explore the expiration payoff

Open a strategy with Index mode selected. Change the illustrative values to match the contract, premium and settlement scenario you want to examine.

Expiration payoff only. No live quotes, margin calculation or account-currency conversion.

How assignment reaches the writer

On receiving an exercise notice for a U.S. listed option, OCC allocates assignment to clearing members with short positions in the same series under its established procedures. The assigned firm then allocates the notice to customer short positions using an approved method. The exercising holder is not necessarily matched with the original seller.

For a cash-settled index option, the assigned writer owes the cash settlement amount. Confirm when it is due under the selected contract and broker procedures. The historical next-business-day convention is not a universal promise for every index product or jurisdiction.