Direct Answer
An OCO (One-Cancels-the-Other) order links two separate orders on the same position so that if either one executes, the other is automatically canceled. The most common use is pairing a profit-target limit order with a protective stop order on an existing position, so a trader does not have to manually cancel the unused order after the other one fills. The main tradeoff is that OCO orders are broker-implemented, not exchange-guaranteed simultaneous cancellations, so in fast-moving or illiquid conditions there is a small, broker-dependent possibility that both legs fill, or that the cancellation lags the fill by a moment.
Key Takeaways
- An OCO order links two orders, most often a limit order and a stop order, so the fill of one cancels the other.
- The most common OCO use case pairs a sell-limit profit target with a sell-stop protective exit on a position you already own.
- OCO orders are also used to enter a position on a breakout in either direction, with a buy-stop above resistance linked to a sell-short-stop below support.
- OCO cancellation is handled by the broker's order-management system, not guaranteed by the exchange itself, so both legs filling is possible in unusual conditions, even if rare.
- An OCO order is the exit-pair building block used inside a bracket order, once an entry order fills, the resulting stop-loss and profit-target pair is itself an OCO order.
What Is an OCO Order?
An OCO order submits two orders together as a linked pair. Both orders are live at the same time, but they are not independent, they share a single underlying intent. When either order executes, whether fully or in some cases partially depending on the broker's handling, the brokerage platform automatically sends a cancellation request for the remaining order.
The two orders in an OCO pair do not have to be the same type. A common combination pairs a limit order (a profit target) with a stop order (a protective exit), because these two orders naturally sit on opposite sides of the current price and represent mutually exclusive outcomes for the same position.
Worked Example: OCO as a Profit Target and Stop-Loss
Assumptions: A trader owns 200 shares of a stock with a cost basis of $50. They want to lock in a gain if the stock reaches $58, but protect against a loss if it falls to $46. This is a hypothetical example with invented numbers.
- Leg 1: Sell limit order at $58 (profit target).
- Leg 2: Sell stop order at $46 (protective stop).
Both orders are submitted together as an OCO pair. If the stock rallies and the $58 limit order fills, the platform automatically cancels the resting $46 stop order, there is no leftover stop order on a position that no longer exists. If the stock instead declines and the $46 stop order triggers, it becomes a market sell order, and the $58 limit order is automatically canceled.
Without the OCO link, the trader would need to manually cancel whichever order did not execute, a step that is easy to forget and that introduces the risk of an unintended second sale if the stock later reverses and hits the un-canceled level.
OCO for Breakout Entries
OCO orders are not limited to exits. Traders anticipating a breakout from a trading range, but uncertain of the direction, can use an OCO pair to enter automatically in whichever direction the market actually moves.
Example: A stock has been trading between $48 support and $52 resistance for several weeks. A trader places a buy-stop order at $52.10 (to catch an upside breakout) linked as an OCO pair with a sell-short-stop order at $47.90 (to catch a downside breakdown). If the stock breaks above $52.10 first, the buy order triggers and the downside sell-short order is automatically canceled. If the stock breaks below $47.90 first, the reverse happens.
This structure avoids ending up with two open positions in opposite directions if the stock eventually reaches both levels at different times, which is the risk of placing the two stop orders independently without linking them.
OCO vs. Bracket vs. OTO
| Structure | What it links | Typical use |
|---|---|---|
| OCO | Two orders, either one cancels the other | Profit target plus stop-loss on an existing position, or a two-direction breakout entry |
| OTO | One parent order that triggers one child order once filled | An entry order that automatically submits a single protective stop |
| Bracket (OTOCO) | One entry order that triggers a linked OCO exit pair | A full pre-planned trade: enter, then automatically stage both a stop-loss and a profit target |
Advantages and Risks of OCO Orders
Advantages
- Removes the manual step of canceling an unused exit or entry order after the other one fills.
- Reduces the chance of an unintended duplicate fill from a stale, un-canceled order.
- Useful for both managing an existing position's exits and entering a breakout in an unknown direction.
Risks and limitations
- OCO cancellation is handled by the broker's order-management system, not the exchange, so there can be a brief delay between one leg filling and the other being canceled.
- In fast or illiquid markets, it is possible, though uncommon, for both legs of an OCO pair to receive at least a partial fill before the cancellation is processed. Review your broker's specific OCO handling and any partial-fill disclosures.
- Each leg of an OCO order still carries its own individual execution risk, a linked stop order can still slip in a gap, and a linked limit order can still go unfilled.
- Not every broker offers OCO orders on every security or order type, and behavior can differ across asset classes.
Practical Checklist Before Placing an OCO Order
- Confirm your broker supports OCO orders for the specific security and order types you want to link.
- Read your broker's disclosure on how partial fills and near-simultaneous triggers are handled between the two legs.
- Set both price levels based on a defined trade plan, not arbitrary round numbers that may sit near common clustering points.
- Check the time-in-force applied to the OCO pair, and confirm whether it matches your intended holding period.
- Verify the cancellation actually processed after one leg fills, do not assume it happened instantly without checking your order history.
Letting One Instruction Close the Position Either Way
The value of pairing two orders is that the position has a defined ending in both directions and neither ending requires you to be watching. That is a structural benefit rather than a tactical one: it removes the moment where a decision has to be made quickly, which is where most plans are abandoned.
The discipline the pair enforces is symmetry. Both prices are chosen together, in the same state of mind, before either is relevant. Choosing a protective level while calm and a target while excited produces a pair that reflects two different traders, and the arithmetic of the trade quietly changes.
The misconception is that cancellation is instantaneous. When one side fills, the other is cancelled by a process that takes some amount of time, and in a fast market both can trigger within that window. The result is an unintended reversed position, which is uncommon but not rare enough to ignore, and is worth knowing about before it happens.
Implementations also differ on partial fills. Some venues cancel the sibling outright when the first side partially fills, leaving the remaining position unprotected; others reduce the sibling proportionally. Which behaviour your platform uses is worth confirming with a small order rather than discovering during a real one.
Frequently Asked Questions
What does OCO stand for?
OCO stands for One-Cancels-the-Other. It describes an order structure in which two orders are submitted together, and the execution of either one automatically cancels the other.
Can both legs of an OCO order fill?
It is uncommon but possible. OCO cancellation is processed by the broker's order-management system after one leg executes, not guaranteed as an instantaneous, atomic exchange-level event. In fast-moving or illiquid conditions, there is a small chance both legs receive at least a partial fill before the cancellation completes. Review your specific broker's OCO handling disclosures.
What is the difference between an OCO order and a bracket order?
An OCO order is the two-leg linked pair itself. A bracket order adds a third leg in front of it: an entry order that must fill first before the linked stop-loss and profit-target OCO pair becomes active. Every bracket order contains an OCO pair, but a standalone OCO order does not require an entry leg, it can be placed directly on a position you already hold.
Can I use an OCO order to enter a position, not just exit one?
Yes. A common use links a buy-stop order above resistance with a sell-short-stop order below support, so the trader automatically enters in whichever direction the stock actually breaks, and the unused side is canceled.
Do both legs of an OCO order need to be the same order type?
No. A typical OCO pair combines a limit order with a stop order, since these two types naturally represent opposite outcomes for the same position, a favorable price target and an unfavorable protective exit.
Is OCO available for every stock or broker?
Not always. OCO order support is broker- and platform-dependent, and availability can vary by security, order-routing venue, and account type. Confirm support directly with your brokerage before relying on an OCO structure.
What happens to an OCO order if one leg partially fills?
Behaviour varies by broker. Some reduce the quantity on the opposite leg to match the remaining position, keeping the two sides in balance. Others cancel the untouched leg entirely on the first execution, which can leave part of the position unprotected. Because the two behaviours produce very different exposure after a partial fill, this is worth confirming in your broker's order documentation before relying on OCO for a position you cannot watch.
Can an OCO order be used across two different securities?
Most retail platforms require both legs of an OCO to reference the same security, because the structure is designed to close or open a single position two possible ways. Some professional platforms support conditional linkage across instruments. Where it is unavailable, the same intent is usually expressed with separate conditional orders, which introduces the risk that both fill before either cancellation is processed.
Do OCO orders survive overnight and across weekends?
That depends on the time-in-force applied to the legs rather than on the OCO structure itself. Legs entered as day orders expire at the close and the linkage expires with them. Legs entered good-till-canceled persist, but many brokers deactivate stop-type legs outside regular hours, so a gap on the next open can move straight through a level the order was meant to act on.
References
"OCO order" is a widely used brokerage-platform term for a linked pair of standard order types, not a separate order category defined directly by the SEC or FINRA. The underlying limit, stop, and order-handling mechanics described on this page follow widely documented U.S. equity market conventions:
- U.S. Securities and Exchange Commission, Investor.gov, Types of Orders: investor.gov: the SEC's investor-education explanation of limit and stop orders, the two order types most commonly linked in an OCO pair.
- FINRA, Order Types and Trading Education: finra.org: guidance on order types and time-in-force conventions that apply to each leg of a linked order.
Because OCO cancellation logic, partial-fill handling, and availability are broker-specific, confirm the exact behavior with your own brokerage's order-entry documentation before relying on one.