Assignment
When an option seller is required to fulfill the contract’s obligation.
Also called: assigned · exercise
Written by Javier Sánchez Ros
In plain language
When a buyer exercises, a seller somewhere is assigned. A short call seller must deliver shares; a short put seller must buy them.
American-style options can be assigned any time before expiration, though early assignment is most common around dividends and deep in-the-money contracts.
Assignment converts an options position into a stock position, often overnight and often much larger than the trader expected.
Worked through
A $340 credit that becomes a $46,000 position
- Sold
- 5 puts, $92 strike
- Premium collected
- $340
- Assigned
- 500 shares at $92
- Obligation
- $46,000
Selling the puts felt small: $340 collected, five contracts, a strike comfortably below the current price. Then the stock fell through $92, the options were assigned, and the account is required to buy 500 shares for $46,000 — an obligation roughly a hundred and thirty times the premium.
This is the asymmetry that defines short options. The credit is fixed and known; the obligation behind it is the full value of the underlying, and it lands on a Monday morning as a margin call rather than as a choice.
Assignment can also arrive early. American-style options may be exercised at any time before expiry, and it becomes considerably more likely around an ex-dividend date on a call you are short — which is a calendar event rather than a market one.
The practical guard is to ask, before selling any option, whether the account could actually take delivery of the underlying position. If the answer is no, the trade is not defined-risk, whatever the premium suggests.
Why it matters
An unexpected assignment can create a position far larger than your account can comfortably hold, turning a defined-risk trade into a margin problem.
Common mistakes
- Holding short in-the-money options through an ex-dividend date.
- Assuming assignment can only happen at expiration.
- Not knowing what stock position an assignment would create, or whether the account could fund it.
Keep exploring
These concepts are connected. Understanding one usually makes the next one easier.
The date an options contract ceases to exist.
An option that currently has intrinsic value.
The capital your broker requires you to post to open and hold a leveraged position.
A cash payment distributed to shareholders out of company profits.
A contract giving the right, but not the obligation, to buy an asset at a set price before expiration.