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Options assignment explained: what happens, when, and why

You sold an option, and now 100 shares appeared in your account. Or vanished. That's assignment. Here's exactly how it works, when it happens, and how to avoid surprises.

Beginner guide · 10-minute read · Updated 2026-10-21

Two words, two sides

Every option has a buyer and a seller. The two words describe each side's part:

• Exercise is what the buyer does. They use their right to buy (a call) or sell (a put) at the strike. See Exercise.
• Assignment is what happens to the seller. They're told they must now keep their promise. See Assignment.

When one buyer exercises, one seller somewhere gets assigned. It's one event, seen from two sides.

What each one does to your account

One standard US stock or ETF contract covers 100 shares.

If you sold a call without owning the shares, assignment leaves you short 100 shares. That's a position with no ceiling on its loss if the stock keeps rising.

When it happens

At expiry: automatic exercise

In the US, equity options that finish $0.01 or more in the money at expiration are usually exercised automatically. This is handled by the Options Clearing Corporation (OCC), the central clearing house, through your broker. You don't need to press anything.

The in-the-money check uses the official closing price, not after-hours trading. Holders can usually send other instructions until a cutoff after the close, often about 5:30 pm ET. Many brokers set an earlier cutoff, so check yours.

Before expiry: early assignment

US stock and ETF options are American-style. The buyer can exercise on any trading day before expiry. So a seller can be assigned early.

Index options like SPX are European-style. They can only be exercised at expiry, and they settle in cash, not shares. No early assignment.

Early assignment is less common than people fear, because exercising early usually throws away time value. It's most likely when:

• The option is deep in the money and has almost no time value left.
• A dividend is coming. A call buyer may exercise the day before the ex-dividend date to own the shares and collect the dividend. This happens when the dividend is bigger than the option's remaining time value.
• Expiry is very close.

How the seller is chosen

When a buyer exercises, the OCC assigns the notice to a broker with sellers of that option. The broker then picks one of its customers, often at random or by a set method like first-in, first-out. Brokers have to tell customers their method.

So you can't know in advance if you'll be the one. You can only know it's possible.

A worked example: a sold put is assigned

You sold one $45 put on a made-up stock, XYZ, for $1.00. You collected $100. At expiry, XYZ closes at $42.

1. The put is $3.00 in the money, so it's exercised automatically.
2. You're assigned. You buy 100 shares at $45. $4,500 leaves your cash.
3. The shares are worth $42 × 100 = $4,200.
4. On paper: −$300 on the shares, +$100 premium = −$200 so far.
5. You now own 100 shares. Their risk is now your risk, starting the next morning.

More on this setup in cash-secured put explained.

A worked example: a bought call you can't afford to exercise

You bought one $50 call for $2.00 ($200). At expiry, the stock is at $53. The call is in the money.

If it's auto-exercised, you'll buy 100 shares at $50. That's $5,000 of stock. If your account has $800 in it, you can't pay.

Brokers handle this in different ways. Some close the option for you before the close. Some exercise and then sell shares, or issue a margin call. Often the simplest move is to sell the option yourself before expiry. You'd get about $3.00 ($300) and never touch the shares.

Pin risk: the expiry-day trap

Pin risk is when the stock closes right at, or very near, your sold strike on expiry day.

Say you sold a $100 call as part of a vertical spread, with a bought $105 call. XYZ closes at $100.02.

• The sold $100 call is $0.02 in the money. It will likely be exercised. You're assigned: short 100 shares.
• The bought $105 call is out of the money. It expires worthless.
• After hours, XYZ jumps to $104. Monday it opens at $106.
• You're short 100 shares from $100. At $106 that's −$600, plus the spread's other results. Your $105 protection already expired on Friday.

This is why many traders close spreads before expiry day, especially when the price sits between or near the strikes. The same applies to 0DTE options on ETFs.

Settlement timing

US stock trades settle one business day after the trade (T+1). Shares from exercise or assignment usually show up in your account the next business day. Your broker's activity page will show the exercise or assignment as its own line.

How to avoid surprise assignment

1. Close sold options before expiry if you don't want shares, especially if they're near the money.
2. Check ex-dividend dates on any sold in-the-money call.
3. Know your account's buying power before holding a bought option into expiry.
4. Read your broker's expiry rules: its cutoff times and what it does with options you can't cover.
5. Never sell an uncovered call unless you can write down the worst case.

Common mistakes

• Thinking out-of-the-money options can't be assigned. Rarely, buyers exercise them anyway, especially after an after-hours move.
• Assuming the long leg of a spread will be exercised for you. If it's out of the money, it won't be.
• Holding a bought option into expiry with no cash to exercise. Sell it first.
• Panicking at early assignment. It's the contract working as written. Check your new position and follow your plan.

Try it today (no money needed)

1. Look up one large dividend stock. Find its next ex-dividend date.
2. Open its chain for the expiry just after that date. Find a call well in the money.
3. Compare its time value (price minus intrinsic value) with the dividend per share.
4. If the dividend is bigger, early assignment of that call becomes more likely. Write that down.
5. Read your broker's help page on expiration and assignment. Note its cutoff time.

Questions