What Is an Option Assignment?

Assignment Explained in Less Than 5 Minutes

person in peach sweater wearing glasses looking at computer
•••

Morsa Images / Getty Images

In the world of options, assignment happens when the holder of an option exercises their right under the contract. The seller of the option is assigned the obligation to follow through on the terms of the options contract, such as buying or selling a number of stocks at a set price.

This article will cover how assignment works, and what everyday investors need to know about it.

Definition and Examples of Assignment

An assignment represents the seller of an option’s obligation to fulfill the terms of the contract by either selling or purchasing the underlying security at the exercise price. Let’s explain what that means in more detail.

When you sell an option to someone, you’re selling them the right to make you engage in a future transaction. For example, if you sell someone a put option, you’re promising to buy a stock at a set price any time between when the transaction happens and the expiration date of the option.

If the holder of the option doesn’t do anything with the option by the expiration date, the option expires. However, if they decide that they want to go through with the transaction, they will exercise the option. 

If the holder of an option chooses to exercise it, the seller will receive a notification, called an assignment, letting them know that the option holder is exercising their right to complete the transaction. The seller is legally obligated to fulfill the terms of the options contract.

For example, if you sell a call option on XYZ with a strike price of $40 and the buyer chooses to exercise the option, you’ll be assigned the obligation to fulfill that contract. You’ll have to buy 100 shares of XYZ at whatever the market price is, or take the shares from your own portfolio and sell them to the option holder for $40 each.

Options traders only have to worry about assignment if they sell options contracts. Those who buy options don’t have to worry about assignment because in this case, they have the power to exercise a contract, or choose not to.

How Does Assignment Work?

The options market is huge, in that options are traded on large exchanges and you likely do not know who you’re buying contracts from or selling them to. It’s not like you sell an option to someone you know and they send you an email if they choose to exercise the contract, rather it is an organized process.

In the U.S., the Options Clearing Corporation (OCC), which is considered the options industry clearinghouse, helps to facilitate the exchange of options contracts. It guarantees a fair process of option assignments, ensuring that the obligations in the contract are fulfilled.

When an investor chooses to exercise a contract, the OCC randomly assigns the obligation to someone who sold the option being exercised. For example, if 100 people sold XYZ calls with a strike of $40, and one of those options gets exercised, the OCC will randomly assign that obligation to one of the 100 sellers.

In general, assignments are uncommon. About 7% of options get exercised, with the remaining 93% expiring. Assignment also tends to grow more common as the expiration date nears.

If you are assigned the obligation to fulfill an options contract you sold, it means you have to accept the related loss and fulfill the contract. Usually, your broker will handle the transaction on your behalf automatically.

What It Means for Individual Investors

If you’re an individual investor, you only have to worry about assignment if you’re involved in selling options. Even then, assignments aren't incredibly common. Less than 7% of options get assigned and they tend to get assigned as the option’s expiration date gets closer.

Having an option assigned does mean that you are forced to lock in a loss on an option, which can hurt. However, if you’re truly worried about assignment, you can plan to close your position at some point before the expiration date or use options strategies that don’t involve selling options that could get exercised.

Key Takeaways

  • An assignment represents the seller of an option’s obligation to fulfill the terms of the contract by either selling or purchasing the underlying security at the exercise price. 
  • If you sell an option and get assigned, you have to fulfill the transaction outlined in the option.
  • You can only get assigned if you sell options, not if you buy them.
  • Assignment is relatively rare, with only 7% of options ultimately getting assigned.