Stop-loss orders explained: triggers, gaps and execution risk

A stop-loss order can help you act on an exit plan, but it does not guarantee your selling price or cap your loss. Understanding the difference between the trigger price and the execution price matters before you use one.

Correction, 7 September 2026: the original example incorrectly implied that an ordinary stop order capped the loss at 10 per cent. The example and related order guidance have been corrected.

How a stop-loss order works

A stop-loss order instructs your broker to attempt a sale when the relevant price reaches a specified trigger, under the broker’s terms. For example, you buy at 200p and set a stop at 180p. That is a trigger 10 per cent below your purchase price, not a guaranteed maximum loss. If the next available execution price is 160p, your loss is 20 per cent before charges. Execution can also be delayed or fail. Hargreaves Lansdown’s order terms explain the risks of gaps, limited liquidity and non-execution.

Hope can make it difficult to reassess a losing position. A share may recover, or its price may keep falling. An exit plan can help structure that decision, but a stop order is only one possible tool and cannot eliminate investment risk.

A predetermined exit instruction can reduce the need for an immediate decision during a price fall. It cannot tell you whether the investment remains good value, and it may sell a holding during a temporary decline.

Getting the level right

There is no universally suitable stop percentage. A 10 per cent trigger is an illustration, not a recommendation. Relevant considerations include the share’s price fluctuations, the bid-offer spread, position size, investment horizon and the broker’s execution rules.

A less liquid small-cap can have a wide bid-offer spread and sharp price movements. Check the price your broker uses to trigger the order: it may differ from the last-traded or indicative price displayed on a chart.

A trigger close to the current price may be reached during an ordinary fluctuation. The share might then recover after your sale, but a recovery is not guaranteed. A price movement alone does not establish whether the business has improved or deteriorated.

A more distant trigger allows a larger fall before an attempted sale. It still does not place a floor under the execution price. Consider the potential loss in pounds as well as the percentage movement, and how it would affect the whole portfolio.

Stop orders do not replace diversification or sensible position sizing. An ISA changes the tax treatment of eligible investments; it does not remove their market or execution risks.

When to set your stop-loss order

If a stop order forms part of your approach, consider its purpose and terms before entering the position. Some long-term investors use other methods of reviewing risk. Using a stop on every investment is not a universal requirement.

Making a plan in advance can help you avoid an impulsive response to a loss. Review the order’s expiry, applicable trading hours and treatment of corporate actions or suspensions. Do not assume a standing instruction remains active indefinitely.

Distinguish a price-based exit rule from the investment case. If you bought a retailer at 400p because you expected better profit margins, a fall to 360p does not by itself prove that expectation wrong. You may still choose a price-based rule, but understand what it measures.

Stop-loss orders versus stop-limit orders

A conventional stop-market order becomes a market order once triggered. Its eventual execution price depends on available buyers and market conditions, rather than being fixed at the trigger. Brokers may implement conditional orders differently, so read the terms for the service you use.

Execution may be below the trigger, particularly after a gap or when few buyers are available. A sell stop-limit order instead activates a limit order with a minimum acceptable execution price. It may remain unfilled if buyers will not pay that price. The SEC’s order guide explains this distinction.

The trade-off is execution flexibility versus a price constraint. Neither order guarantees that you will exit the position. A broker’s separately offered guaranteed-stop product, where available, has its own conditions and possible charges; it is not the same as an ordinary stop order.

A stop-limit uses two different prices

Consider a hypothetical sell stop-limit with a trigger at 180p and a minimum selling price of 175p. Once the trigger condition is met, buyers willing to pay 178p could allow a sale at that price. If the market gaps down and the best available bid is only 160p, the instruction cannot sell at 160p because that is below its limit. The shares may remain in your account while their value falls further.

The trigger decides when the instruction becomes active. The limit controls which sale prices are acceptable afterwards. Setting the second number five pence below the first does not reserve a buyer somewhere in that interval. It leaves a range of permitted execution prices, subject to demand and the broker’s rules. Nor does a later return above 175p prove the order filled: check its status and any trade confirmation.

How a trailing stop changes the trigger

A trailing stop adjusts its trigger after favourable price movements. Suppose a hypothetical sell trailing stop follows the broker’s reference price by 10 per cent. At 200p, the trigger would be 180p. If that reference rises to 240p, the trigger could move to 216p: 240p multiplied by 0.90. A subsequent fall does not automatically lower that trigger again. These percentages illustrate the arithmetic, rather than a suitable setting for every investment.

Check whether the resulting instruction is a market order or a limit order. That determines whether execution can occur below the trigger or whether a price restriction may prevent a sale. Also check which price is followed, when the broker updates the trigger and whether the product is available for that security. The SEC explains the trailing mechanism and broker-specific trigger conditions.

What a stop can and cannot tell you

Think of the stop price as the point at which an instruction becomes active, rather than a price reserved for you. In a fast market, the next available price can be quite different. A share can also move between one trading session and the next without passing through every price on your screen. That is why a stop placed above a gap does not fill the gap or guarantee that someone will buy at your chosen level.

A second distinction is between the loss on the shares and the total cost of the trade. In the 200p-to-160p example, the share-price loss is 40p per share. On 100 shares, that is £40 before charges. Dealing fees and any other applicable costs affect the total result. An order instruction does not make those costs disappear, and a percentage calculated from the share prices alone should be labelled accordingly.

For example, an order that has expired is not still protecting a holding simply because you remember setting it last month. A cancelled order is different from an executed order, and a triggered instruction is not proof that the sale has completed. The broker’s order status and trade confirmation are the records to check when establishing what happened.

For the other side of the distinction, our limit-order guide explains price boundaries and unfilled trades. A sell limit can constrain the execution price, but it can also leave the shares unsold.

When a stop-loss order triggers: check its status

A triggered instruction may be pending, executed, partially executed where supported, or unsuccessful. Check the order status before submitting another sell instruction: duplicating an order can create an unintended trade. Check that any cancellation has been accepted rather than assuming a request cancels it immediately.

An alert that asks you to review a price movement is different from an order instructing the broker to attempt a trade.

A stop order can put part of an exit plan into practice, but the loss you intend to tolerate and the loss you actually incur can differ. Choose an approach that fits your circumstances, and understand its limits before relying on it.

The Short Version

• The stop price triggers an instruction; it is not a guaranteed selling price.
• A gap or a lack of buyers can produce a larger loss than the trigger percentage suggests.
• A stop-limit adds a price constraint but can leave the position unsold.
• Check your broker’s trigger, expiry, trading-hours and execution rules.
• Check the order status before placing another instruction.
• Stops are one risk-management tool, not a substitute for diversification or position sizing.

Related Reads

• how the bid-offer spread affects trading costs
• how to decide when to take profits
• how a balanced portfolio helps manage risk

Nothing in this article is financial advice. Tax rules change frequently. Check the current ISA allowance, CGT exemption and relevant rules on HMRC’s website or consult a qualified financial adviser for your specific situation.

Money & Markets is a guide to personal finance and investing for people who want to understand the world they live in, updated as rules and markets change.

Disclaimer: The value of investments can go down as well as up, and you may get back less than you invest. This article is for informational and educational purposes only and does not constitute financial advice. Always do your own research and consider seeking independent advice before making any investment decision.