Exercise and assignment.
In plain English
Exercise and assignment are the two sides of the same event: a holder converts the option into stock at the strike price, and a selected seller of that contract is obligated to complete the trade. American-style options can be exercised on any trading day up to expiration, while European-style options can be exercised only at expiration. Assignment is allocated by the clearing organization and then by the broker, often at random, so a seller cannot know in advance which day it will land. In-the-money contracts are generally exercised automatically at expiration under standard clearing procedures. Early assignment on calls tends to cluster around dividend dates.
01Why it matters
A seller of options can wake up owning or owing 100 shares per contract, and the cash or margin to settle that has to already be there.
02The math, step by step
Sell one 50 strike call and get assigned. That means delivering 100 shares at 50, or 5,000 total. If the shares were bought at 40, the sale locks in a 10 per share result, or 1,000, and the option premium collected sits on top of that. If the shares are not owned, the account ends up short 100 shares instead.
Illustrative example. The amounts here are hypothetical, chosen to show how the math works, not real quoted rates or figures.
03What this is NOT
Exercise is not the same as selling the contract. Selling passes the position to someone else in the market and ends the exposure in cash. Exercise turns the contract into an actual stock transaction at the strike, which needs the shares or the money to be available.
04Receipts
Every figure on this page is sourced to a primary document. Tap to open the original.
Plain-English answers from our glossary. Receipts included. Never advice.
Educational tool. Answers come only from ClearMoneySchool's published glossary and are not advice. Why we never give advice