What is Reduce-only?

Reduce-only is a parameter that guarantees your order can only reduce or fully close an existing position.

It will never increase your position size or open a new one in the opposite direction.

Why use Reduce-only?

Reduce-only is an important risk management tool for margin and futures trading.

It is especially useful when you have multiple active orders at the same time. If one of them closes your position before the others are executed, Reduce-only prevents the remaining orders from accidentally opening a new position.

It also helps prevent any order from increasing your position beyond its current size.

Where is it available and how to enable it?

Reduce-only is available only on margin and futures trading upon placing Advanced orders.

Web version

1. Go to the Trading page and select a trading pair.

2. In the order form, choose an advanced order type (e.g., Advanced limit, Stop-Market, Stop-Limit, Multi-Limit, OCO).
3. Check the Reduce-only checkbox.
4. Enter the required order details (price, amount, etc.).
5. Click “Buy” or “Sell”, then confirm the order.

For more information on placing orders in the web version, refer to the article: https://help.whitebit.com/hc/en-gb/articles/9798180636189-How-to-place-an-order-from-the-site 

Mobile app

1. Go to the “Trade” section in the “Exchange” mode and select a pair of assets from the drop-down list in the upper left part of the screen.
2. You can also use the “Markets” tab. Use the search, select an available pair and click on it. You will be redirected to a page with a chart. From there, click Buy or Sell.
3. When clicking the “Buy” or “Sell” button, you are redirected to the trading terminal.
4. In the order type drop-down, select an advanced order type (e.g., Advanced Limit, Stop-Market, Stop-Limit, Multi-Limit, OCO).
5. Enter the required order details (price, amount, etc.).
6. Enable the Reduce-only parameter.
7. Click “Buy” or “Sell”, then click “Confirm” in the confirmation window.

For more information on placing orders in the mobile app, refer to the article: https://help.whitebit.com/hc/en-gb/articles/9797858885533-How-to-place-an-order-from-the-app 

 

Please note that Reduce-only is not available for Basic Orders in the web or mobile interface.

However, Reduce-only is available via API for all order types.

How does it work?

The parameter applies the following system validations:

• Order size exceeds your position → automatically reduced to match it on placement, modification, and execution.
• Position is fully closed → all remaining reduce-only orders are cancelled automatically.
• No open position, or order direction matches position direction → order won't be placed.

Automatic Reduce-only

Reduce-only is automatically applied when you use:

• Closed by Market
• Close all positions
  
   

This ensures that closing your position will never result in opening a new one.

For Limit Сlose orders, you can enable or disable Reduce-only manually.

Please note: Reduce-only is not compatible with TP/SL orders.

Order size adjustment (Clipping)

If your order size exceeds your current position, it will be automatically adjusted.

For example, you have a long position of 1 BTC on futures trading (BTC-PERP).

You place a Reduce-only sell order for 1.6 BTC, which is larger than your position.

The system will then validate the order by checking whether a position exists, whether the order size is in the opposite direction, and whether it exceeds the current position size.

In this case:

• The sell order will be reduced to 1 BTC and executed at the market price
• The remaining amount will be ignored
• The position will be closed completely

Clipping on Order Modification

If you modify an existing Reduce-only order and increase its size beyond your position, the system will automatically adjust it again.

For example, you have a long position of 1 BTC on BTC-PERP.

1. You place a Reduce-only sell limit order for 1 BTC at $45,000.
2. The system accepts the order and adds it to the order book.
3. You modify the order amount from 1 BTC to 5 BTC.
4. The system detects that the new amount exceeds your position size.
5. The system automatically adjusts the order amount from 5 BTC back to 1 BTC.
6. The market reaches $45,000 — the order executes 1 BTC, closing your position completely.

Multiple Reduce-only orders and auto-cancellation

You can place several reduce-only orders at different price levels. Each order is validated against your current position size at placement — independently of other open orders. It is then re-validated at the time of execution, ensuring the order always reflects the actual remaining position size. Once your position is fully closed, all remaining reduce-only orders are automatically cancelled.

For example, you have a long position of 1 BTC on BTC-PERP at $45,000.

1. You place a Reduce-Only sell limit Order A for 0.6 BTC at $44,000.
2. You place a Reduce-Only sell limit Order B for 0.7 BTC at $43,500.
3. The market drops to $44,000 — Order A executes, leaving your position at 0.4 BTC.
4. The market continues to $43,500 — Order B is automatically adjusted to 0.4 BTC and executed.
5. Your position is fully closed (0 BTC remaining).
6. Any remaining Reduce-only orders are automatically cancelled.

When can Reduce-only orders be rejected?

No Open Position

If you place a Reduce-Only order but have no open position in that market, the order is rejected, as there is nothing to reduce.

For example, you have no open position on BTC-PERP.

1. You attempt to place a Reduce-only sell limit order for 0.5 BTC.
2. The system detects that no position exists.
3. The order is rejected.

Same Direction as Position

If a Reduce-only order is in the same direction as your open position, the order is rejected. Executing it would increase your position, which Reduce-only is designed to prevent.

For example, you have a long position of 1 BTC on BTC-PERP.

1. You attempt to place a Reduce-only buy limit order for 0.5 BTC (same direction as your position).
2. The system detects that the order side matches the position side.
3. The order is rejected. 

API

The “reduceOnly” parameter is supported across collateral order management endpoints — it can be included in requests to place a reduce-only order and appears in responses to indicate whether an existing order has the flag enabled.

Error response

If a reduce-only order is placed when no position exists, or the order would increase the position, the following error is returned:

{
"code": 116,
"message": "Validation failed",
"errors": {
"reduceOnly": ["Reduce-only: Position doesn't exist or wrong side"]
 }
}