What Is Assignment in Options Trading?

Assignment is what happens to an option seller when the buyer on the other side decides to exercise. You don’t get a say in it, and you don’t get advance warning beyond what the market itself tells you - if you’ve sold an option that finishes in the money, there’s a real chance you’ll wake up with a new stock position you didn’t explicitly order.

For a short call, assignment means selling 100 shares at the strike - shares you deliver whether you own them (a covered call) or not (a short call). For a short put, it means buying 100 shares at the strike, whether or not you wanted to own the stock at that price.

Who Actually Picks the Seller

Here’s the part that surprises most new sellers: nobody at your brokerage is choosing who gets assigned. When an option holder exercises, the request goes to the Options Clearing Corporation (the OCC), which randomly selects one brokerage firm holding a matching short position. That firm then uses its own method - usually random or first-in-first-out - to pick which of its customers gets assigned.

That randomness means two traders holding the identical short option, opened on the same day, can get completely different outcomes. One gets assigned; the other doesn’t. There’s no way to improve your odds except by closing the position before expiration.

When Assignment Actually Happens

Most assignment happens right at expiration, when any option that’s even a penny in the money is auto-exercised under the OCC’s exercise-by-exception rule. But American-style options - which is nearly every US equity option - can be exercised any day the holder chooses, not just at expiration.

Early assignment is rare in practice, but it clusters around one specific situation: a deep in-the-money short call, right before the stock goes ex-dividend. If the call’s remaining extrinsic value is smaller than the upcoming dividend, the holder is often better off exercising early to capture the payout - which hands you the stock sale and takes the dividend away from you in the same move.

A Simple Example

Say you’ve sold a Coca-Cola $92 call, and KO is trading at $96 the day before an ex-dividend date. The call has very little time value left - maybe $0.36 - but the dividend is worth $0.53. For the holder, exercising early to grab that $0.53 is the better trade than holding the option. You get assigned: your 100 shares are sold at $92, and the dividend goes to the new owner instead of you.

Outside of that dividend-driven case, early assignment is uncommon. Most sellers never see it happen on an out-of-the-money or only slightly in-the-money position, because there’s rarely a reason for the holder to give up remaining time value just to exercise early.

What Assignment Actually Costs You

Assignment itself isn’t a penalty - it’s just the obligation you agreed to when you sold the option, and the premium you collected was the payment for taking it on. The real cost shows up in two places: you might miss a dividend you were counting on, and you lose the ability to choose your own exit price, since the trade happens at the strike instead of wherever you might have closed it.

If you’d rather control the timing yourself, the fix is simple: close the position - buy back a short call or short put - before it gets deep enough in the money for assignment to become likely.

Where this is used

• Short Call
• Short Put
• Cash-Secured Put
• Covered Call

Related terms

• Exercise
• Assignment Risk
• Short Position

See what assignment would do to a real position: open the options calculator and check a short option’s payoff at and below the strike.

This article is for educational purposes only and does not constitute financial, investment, legal or tax advice. Options trading involves substantial risk and is not suitable for all investors.