Options Assignment

Definition

Every options contract creates two roles: the buyer, who holds the right to exercise, and the seller (or writer), who carries the obligation to honor that exercise. Assignment is the moment that obligation crystallizes — when the seller is notified that a buyer somewhere has exercised, and shares must now change hands at the strike price. For a covered call writer, assignment means delivering 100 shares per contract at the strike and receiving cash. For a cash-secured put writer, it means buying 100 shares per contract at the strike using the cash that was set aside.

Exercise and assignment are two sides of the same transaction. When a buyer files an exercise notice, the Options Clearing Corporation (OCC) receives it, then randomly selects a broker holding short positions in that contract. The broker, in turn, randomly assigns one of its short customers. The seller has no control over whether or when they are picked — only the contract’s status (in-the-money, deep ITM near a dividend date) influences the likelihood.

Assignment overwhelmingly happens at or just after expiration, when in-the-money options are automatically exercised by the OCC. Early assignment — exercise before expiration — is rare and typically only economically rational in narrow cases: deep ITM calls on a stock about to pay a dividend, or deep ITM puts where the time value has collapsed below the carry cost of the strike’s cash.

Why it matters

Key takeaways

Buyers have the right; sellers have the obligation. Assignment is the seller-side event triggered when a buyer exercises.
The OCC randomly selects which seller is assigned. The seller cannot predict or control the timing — only the option's moneyness signals the likelihood.
Assignment is most common at expiration. Early assignment occurs primarily for deep ITM calls before ex-dividend dates and deep ITM puts late in the cycle.
For covered call writers, assignment is the strategy working — shares are called away at the strike for a profit (plus the premium already collected).
After assignment, the option position disappears from the account and the stock position changes by 100 shares per contract. The cash side adjusts automatically.
Assignment anxiety drives unnecessary trade closures. For covered call writers in particular, being assigned is usually the best of two acceptable outcomes.

What you see when it happens

Read it as: Assignment is administrative, not adversarial. The OCC’s random selection means no individual buyer “targets” any particular seller — the seller simply wakes up to find shares moved and cash adjusted. There is no negotiation, confirmation, or response required.