How assignment works

Assignment in options trading refers to the obligation of an option writer to fulfill the terms of the option contract when the option is exercised by the holder.

Assignment is a critical concept for anyone writing (selling) options. When you sell an option, you are taking on an obligation. For a call option, the writer is obligated to sell the underlying asset at the strike price if the holder exercises the option. For a put option, the writer is obligated to buy the underlying asset at the strike price if the holder exercises. Assignment is typically random among all writers of the same option series, unless specific rules apply (like FIFO at some brokerages). The options clearing corporation (OCC) uses a lottery system to assign exercise notices to clearing members, who then allocate these notices to their customer accounts that are short the option. This process means that even if an option is deep in-the-money, a specific writer might not be assigned, or they might be assigned unexpectedly early before expiration.

Assignment primarily impacts the writer of the option, as it forces them to take a specific action regarding the underlying asset. For call writers, assignment means potentially selling shares they don't own (requiring them to buy shares at market price to cover, which can be very expensive if the market price is much higher than the strike price), or selling shares from their existing holdings. For put writers, assignment means buying shares they might not want, or at a price higher than the current market value. The impact on option prices themselves is indirect. The *risk* of assignment, especially for deep in-the-money options nearing expiration, is factored into the option's premium by market participants. This risk can influence how quickly an option's extrinsic value decays or how volatile its price might be as expiration approaches, particularly if the underlying asset's price is hovering around the strike price. Understanding assignment is key to managing risk for options writers.

Why it matters

- Assignment dictates the direct action an option writer must take concerning the underlying asset, leading to either buying or selling shares.
It brings significant financial implications for option writers, as they face the obligation to fulfill the contract at the strike price, regardless of the current market price.
Understanding assignment risk is crucial for managing potential losses, especially when writing deep in-the-money options or options nearing expiration, influencing strategic decisions like rolling or closing positions.

Common mistakes

- A common mistake is for option writers to assume they won't be assigned until expiration, leading to unexpected obligations and potential capital requirements.
Another error is not having sufficient capital or the underlying shares available to meet the assignment obligation, which can result in margin calls or forced liquidation.
Many writers fail to monitor their short option positions closely, particularly when options go deep in-the-money, increasing the likelihood of early assignment before they have a chance to adjust their strategy.

FAQs

Can an option be assignedBefore expiration?

Yes, American-style options can be exercised by the holder and therefore assigned to the writer at any time up to and including the expiration date. This often happens if an option goes deep in-the-money or if there's an impending dividend payment.

What happens if I'm assigned a call option?

If you are assigned a call option, you are obligated to sell the underlying asset at the strike price. If you don't own the shares, you'll have to buy them at the current market price to fulfill the obligation, which can result in a loss if the market price is higher than the strike price.

How does assignment differ from exercise?

Exercise refers to the option holder's decision to invoke their right to buy or sell the underlying asset. Assignment is the resulting obligation placed on an option writer to fulfill that exercised contract.