Buy to open vs sell to open: what they mean
On an options ticket, every order has two parts: buy or sell, and open or close. "Open" starts a new position. "Close" ends one you already have. Mixing them up can turn a simple exit into a brand-new trade.
The four actions
| Action | What it does | Money |
|---|---|---|
| Buy to open | Starts a new long option position. You own the option. | You pay the premium |
| Sell to close | Ends a long option you already own. | You receive the premium |
| Sell to open | Starts a new short option position. You wrote the option and took on an obligation. | You receive the premium |
| Buy to close | Ends a short option you already have. | You pay the premium |
The pairs go together: buy to open → sell to close, and sell to open → buy to close.
Why options need "open" and "close"
With shares, selling usually just means getting rid of shares you own. Options are different because you can sell an option you do not own. When you do, you are creating a new contract and taking the obligation side of it. So the broker needs to know: are you exiting something you hold, or starting something new?
Buy to open: you own the right
When you buy to open a call or a put, you pay the premium and get a right, not an obligation. A call gives you the right to buy 100 shares at the strike. A put gives you the right to sell 100 shares at the strike.
For a single long option, the most you can lose is what you paid, plus fees.
Example numbers
Buy to open 1 call at $2.00 → you pay 2.00 × 100 = $200.
Later the call is worth $3.00. You sell to close → you receive 3.00 × 100 = $300.
If the call instead falls to $0.50 and you sell to close: 50 − 200 = −$150. If it expires worthless: −$200, the full premium.
Sell to open: you took on the obligation
When you sell to open, someone else buys the right and you take the other side. You are paid the premium now, and that premium is the most you can make on that option. If you sell a call to open, you may have to sell 100 shares at the strike. If you sell a put to open, you may have to buy 100 shares at the strike.
The risk depends on what else you hold:
- A call sold against 100 shares you own is a covered call.
- A put sold with cash set aside is a cash-secured put.
- A short option paired with a long option on the same stock and expiration can form a spread with a capped loss, like a bull put spread.
- A call sold with nothing to cover it is a naked call. Its loss has no fixed cap, because the stock can keep rising. Brokers usually require a higher approval level for it.
Example numbers
Sell to open 1 put at $1.50 → you receive 1.50 × 100 = $150.
Later the put is worth $0.50. You buy to close → you pay 0.50 × 100 = $50.
If the stock drops and the put is worth $4.00 when you buy to close: 150 − 400 = −$250.
The costly mix-up
Suppose you bought 1 call to open and now want out. The right order is sell to close. If you send sell to open instead, you are asking to write a new call on top of the one you hold. Depending on your broker and your options approval level, the order may be rejected or handled differently from what you meant. The risk is bigger when the quantity is off too, for example selling 2 when you only hold 1, because the extra contract would be a new short position.
The reverse also happens. Someone who sold a put to open wants to exit and accidentally sends buy to open. Now they hold a long put on top of the short put instead of closing it.
The fix is simple: before you submit, read the action and quantity on the ticket and ask whether you are starting something or ending something.
Spreads use both at once
A multi-leg ticket can show one leg as buy to open and the other as sell to open. For example, a bull call spread is buy to open a lower-strike call plus sell to open a higher-strike call. When you exit, both legs flip: sell to close the long call and buy to close the short call. See the debit spread calculator for that math.
What happens if you do nothing
If you hold an option to expiration instead of closing it:
- Out-of-the-money options generally expire worthless.
- Options that are in the money by $0.01 or more are generally exercised automatically unless instructions say otherwise. A long call becomes 100 shares bought at the strike; a short put can become 100 shares you have to buy.
- Your broker may have its own rules near expiration, such as closing positions if the account cannot cover the exercise. Check the broker’s expiration policy.
Quick ticket check
- Is this opening a new position or closing one I already have?
- Does the quantity match what I hold, if I am closing?
- Am I paying (debit) or receiving (credit), and does that match the action?
- Can I state the max loss of the position after this order fills?
FAQ
What does buy to open mean?
Buying an option to start a new long position. You pay the premium and get the right, but not the obligation, to buy (call) or sell (put) 100 shares at the strike.
What does sell to open mean?
Selling an option you do not already own to start a new short position. You receive the premium and take on the obligation to sell (call) or buy (put) 100 shares at the strike if assigned.
What is the difference between sell to open and sell to close?
Sell to close exits an option you already own. Sell to open creates a new short option position with an obligation attached.
When do I use buy to close?
To exit a short option position you opened with sell to open. You pay the current premium to end the obligation.
What happens if I choose the wrong one?
You may open a new position instead of closing your existing one, or the broker may reject the order based on your approval level. Always check the action and quantity before submitting.
Educational only. This page explains order mechanics with example numbers. It is not investment advice, not a recommendation to buy or sell anything, and not a broker. Check your own broker’s rules, fees and assignment terms before you trade.