What Is a Reduce-Only Order?

Learn how a reduce-only order closes or shrinks a derivatives position without reversing it, how venues handle excess size and competing exits, and what the instruction does not guarantee.

For educational purposes only; not investment advice. Leveraged digital-asset derivatives can cause rapid and substantial losses.

Direct answer

A reduce-only order is an instruction attached to a derivatives order that allows execution only to the extent that it reduces an existing position. It must not increase exposure or turn a long position into a short position, or vice versa. Traders commonly use it for take-profit and stop-loss exits when more than one closing order may be active.

Reduce-only is a position constraint, not an execution guarantee. It does not guarantee a fill, a trigger price, a limit price, protection from slippage, or protection from liquidation. The exact result of an invalid or oversized order is venue-specific: the platform may reject it, cancel it, or reduce its executable quantity.

How it works

Let the signed position before a fill be q and the proposed position change be delta. A valid reduce-only fill satisfies |q + delta| ≤ |q| and does not cross through zero. The trading engine normally applies this check when an order is accepted and/or when it matches, because the position and other open orders can change in between.

A practical evaluation has four parts:

Confirm that a position exists in the opposite direction from the order: a sell can reduce a long, and a buy can reduce a short.
Determine the remaining reducible quantity after earlier fills, manual closes, liquidation, and relevant open exit orders.
Execute no more than that remaining quantity under the venue’s price, margin, and order-type rules.
Cancel, reject, or resize any remainder according to the venue’s documented policy.

Competing exits require special attention. Coinbase documents automatic cancellation when the position no longer exists; Kraken documents automatic reduction of an order larger than the open position; Bybit documents quantity adjustment or cancellation based on the position and other active orders. These are implementation examples, not a universal sequence or priority rule.

Example

A trader is long 1 BTC perpetual contract and places two reduce-only sell orders for 1 BTC each: a take-profit limit and a protective stop. If the take-profit closes the entire position first, the stop must not execute as a new short. Depending on the venue and order types, the stop or its resulting order may be canceled, rejected, or reduced to zero.

If the first order closes only part of the long, the second order may execute only against the remaining long quantity. The trader should verify the order history and current position rather than assume that the interface has linked the exits as an OCO pair; reduce-only and one-cancels-the-other are distinct instructions.

Risks and controls

No fill guarantee: a limit order may remain unfilled, while a market or triggered order may fill only partially. Keep liquidation distance and available margin under review.
Trigger and fill differ: a stop trigger only activates an order. The trigger source, price protection, liquidity, and slippage determine whether and where it fills.
Venue rules differ: order-entry checks, match-time checks, reserved quantities, and cancellation priority are not standardized. Read the current rules for the specific product and position mode.
State can change first: a manual close, another strategy, liquidation, or an earlier fill can make a resting order invalid before it reaches the book or market.
API mistakes happen: confirm that the reduce-only flag was accepted in the order response, and reconcile open orders, fills, and positions after reconnects or retries.
It does not cap loss: fees, funding, gaps, liquidation, platform outages, and insolvency risk remain. Size the position so a failed exit process is survivable.

Common misconceptions

“Reduce-only means close immediately.” It restricts position effect; time in force, price, and liquidity still govern execution.
“The full submitted quantity is guaranteed to remain open.” A venue may shrink or cancel quantity as the reducible position changes.
“Every take-profit or stop is automatically reduce-only.” Some products enforce this, while others require an explicit flag. Check the order confirmation.
“Reduce-only is the same as OCO.” Reduce-only prevents exposure from increasing; OCO links orders so execution or triggering of one cancels another. A venue may support either or both.

Sources

Reduce only (International Derivatives) - Coinbase (accessed: 2026-08-21)
Order types in Derivatives trading - Kraken (accessed: 2026-08-21)
Reduce-Only Order - Bybit (accessed: 2026-08-21)