Option Assignment Explainer
Option assignment is the notice that requires a writer to perform the obligation in a short option contract. A short call may require delivery of the underlying at the strike, while a short put may require its purchase. Cash-settled options instead produce a cash obligation.
Exercise notices pass through the clearing system to brokerage firms, which allocate them among customers with matching short positions under disclosed procedures. The writer cannot identify or choose the exercising holder, and closing after an assignment cutoff may be too late to prevent the result.
American-style options can generally be exercised before expiration, so assignment risk exists while the short position remains open. Dividend timing, low remaining time value, hard-to-borrow shares, and deep intrinsic value can make early call or put exercise more likely.
Assignment can break one leg of a spread, create shares, consume cash, produce a short stock position, or trigger margin demands. Traders should understand broker notifications, settlement, exercise-by-exception rules, and how the remaining legs behave before relying on a multi-leg payoff diagram.
Calls can require delivery; puts can require purchase.
Cash-settled products use a payment instead.
The exercising holder is not matched directly with a chosen writer.
Broker procedures determine customer allocation.
Spreads may become shares plus a remaining option.
Cash, borrow, and margin must be ready.
Explore more "Explainers"
Discover additional explainers across politics, science, business, technology, and other fields. Each explainer breaks down a complex idea into clear, everyday language—helping you better understand how major concepts, systems, and debates shape the world around us.