A spread may have bounded theoretical expiration risk while still creating stock, cash or margin consequences if one short leg is assigned.
Assignment applies to the short contract
The holder of an American-style equity option can generally exercise before expiration. The corresponding short position may then be assigned. The broker handles allocation, and the writer typically does not choose the timing. A protective long leg does not automatically exercise at the same instant.
The result can be a temporary stock position, financing requirement or dividend-related exposure. Broker procedures, cutoffs and risk controls matter.
Why dividends and expiration deserve attention
Early exercise can become more relevant around an ex-dividend date when an in-the-money call has little remaining time value. Near expiration, a stock closing near a strike creates uncertainty about exercise and assignment. After-hours movement can add exposure before the resulting position can be managed.
Do not assume “defined risk” means “no assignment management.” It describes a payoff relationship under specified contracts and settlement assumptions.
Pre-expiration checklist
Check short-leg moneyness and remaining extrinsic value, the ex-dividend calendar, exercise style, settlement, broker cutoffs, account buying power and the consequence of each single-leg assignment. If you do not understand the resulting stock position, do not wait until expiration to learn it.