Trading Order Types Glossary: Market, Limit, Stop and More
Trading order types determine how an instruction to buy or sell is submitted, activated, matched and potentially cancelled. The difference between market, limit, stop, stop-limit and time-in-force instructions affects execution price, fill probability and risk. This practical glossary explains the language of order tickets and electronic markets.
Every order type has a trade-off. Urgent execution can consume scarce liquidity; a restrictive price can leave the trade unfilled; a stop can activate during a gap. These definitions are educational, and the rules of the actual exchange or broker always determine what happens to a live instruction.
Trading order types: definitions and examples
Market order
An instruction to trade promptly at available prices. A purchase consumes offers and a sale consumes bids. It prioritises the likelihood of a fill over control of the exact price and can be unexpectedly expensive when the order exceeds displayed depth.
Limit order
An instruction to buy at no more than the specified limit, or sell at no less than it. The limit restricts execution price, but an order may remain unfilled or partially filled as the market moves away.
Marketable limit order
A limit order priced so that it can immediately interact with the opposing quote. It combines a willingness to trade at once with a maximum acceptable purchase price or minimum acceptable sale price, although depth can still restrict quantity.
Resting limit order
An order that remains on the book waiting for a matching counterparty rather than crossing the spread immediately. It may earn a better price but carries non-execution risk and can be selected adversely when new information moves prices against it.
Stop order
An instruction that becomes active after a defined market trigger. A traditional stop typically turns into a market order when triggered, so the eventual execution price can differ materially from the displayed trigger level during a gap.
Stop-limit order
An order that becomes a limit order after its stop condition activates. It constrains execution price but can fail to execute at all if the market passes through the limit without matching available liquidity.
Trailing stop
A stop trigger adjusted in a favourable direction by an amount or percentage under the provider’s rules. It does not move back when price reverses; it remains subject to gaps, trigger conventions and execution uncertainty.
Stop-loss instruction
A risk-management label commonly applied to an order intended to exit when price moves adversely. Its actual mechanics depend on whether it is a stop-market, stop-limit, guaranteed stop or another broker-specific order.
Take-profit order
An instruction intended to reduce or close exposure after a favourable price movement. A take-profit implemented as a limit order can be left unfilled in fast or thin markets even if a chart briefly touches its level.
Buy stop
A stop order whose activation price is generally above the current market for a long entry or a short exit. A rising price triggers its activation; it should not be confused with a buy limit placed below the market.
Sell stop
A stop order whose activation price is generally below the current market for a long exit or a short entry. It may be used for risk control but does not guarantee the final selling price.
Buy limit
An instruction to buy at or below a designated price. It can be used to seek a lower entry price, but the market may never trade at that level or there may be insufficient sell quantity available.
Sell limit
An instruction to sell at or above a designated price. It may be used for a planned exit or passive offer, but touching the price does not guarantee that an individual order obtains queue priority or executes.
Day order
An order that expires at the end of the relevant venue or broker’s trading day if not filled. Session definitions and treatment of extended-hours trading need checking before relying on automatic expiry.
Good-till-cancelled
A time-in-force convention that retains an eligible order until filled or cancelled, subject to platform expiry limits and corporate-action handling. Its name does not imply truly indefinite persistence on every platform.
Good-till-date
An instruction for an order to expire on a specified date or time under the broker’s settings. Time-zone and venue-session conventions matter, especially around weekends and market closures.
Immediate-or-cancel
An order condition permitting immediate execution of available quantity while cancelling the unfilled balance. It differs from a fill-or-kill instruction because partial execution is normally permitted.
Fill-or-kill
An instruction requiring the entire specified quantity to execute immediately or the instruction to be cancelled. It is useful where partial exposure would be unacceptable, but it can sharply reduce fill probability.
All-or-none
An order condition requiring a complete fill but not always immediate execution. Availability, exchange support and venue rules differ, and a broker may implement or reject it differently from a fill-or-kill order.
Market-on-open
An instruction targeted for execution at the opening auction under a venue’s rules. It can participate in opening price discovery, but the auction price is unknown in advance and submission cutoffs may apply.
Market-on-close
An instruction intended to execute in the closing auction or closing process. It does not promise today’s last continuous-trading quote and may be subject to exchange restrictions and imbalances.
Limit-on-close
An auction-linked order with an execution price limit. It seeks closing-price participation only if auction conditions satisfy the limit; a valid unfilled result is possible.
Post-only
A condition commonly available on electronic venues requiring an order not to take liquidity immediately. If it would cross the book, the venue may reject, reprice or cancel it according to published rules.
Reduce-only
A venue or platform instruction intended to prevent the order from increasing the net position. It is common in some derivatives markets but exact treatment of opposing orders and partial fills is product-specific.
Bracket order
An arrangement linking an entry to associated exit instructions, often one profit-taking and one protective stop. The order-management system may cancel or adjust siblings, but linked behaviour is not identical across brokers.
One-cancels-other
A link between orders under which a fill or trigger of one instruction cancels the other according to specified rules. Communications delay and partial fills can create temporary exposure before the cancellation is confirmed.
One-triggers-other
An order sequence where one event activates a second instruction. It can automate a conditional plan, but the second order still follows its own execution rules and may not fill.
Iceberg order
An instruction exposing only part of a larger desired quantity at a time, when permitted. Refreshing displayed slices does not conceal the order from all counterparties and may change queue priority.
Pegged order
A limit order whose reference price adjusts according to a market benchmark such as the best bid, offer or midpoint. Reference movements and platform constraints determine whether it takes or provides liquidity.
Discretionary order
An instruction with a displayed price and conditional authority to execute at a more aggressive price under defined conditions. The permitted range, regulatory status and availability vary by venue.
Partial fill
Execution of only part of the requested order quantity. The residual order may remain active or be cancelled according to time in force, causing actual exposure to differ from the original trading plan.
Queue priority
The order in which resting instructions are eligible to match, often governed by price-time or another venue rule. An order can trade at its limit without necessarily receiving an execution if other orders had priority.
Order routing
The selection of venue, dealer or execution method for an order. The best displayed quote on one venue may not reflect all executable liquidity, routing fees, speed or the client’s wider execution interests.
Smart order routing
Technology that distributes or redirects orders among venues according to routing rules. Its name is not evidence of superior outcomes; order type, hidden liquidity, cost and venue connectivity determine performance.
Trigger price
The observable input, such as last trade, bid, ask or mark price, used to activate a conditional order. Different trigger sources can cause orders to fire at different moments even on the same chart.
Guaranteed stop
A product-specific feature that may promise an exit price subject to contractual terms, eligible instruments, premiums and restrictions. It must not be assumed to exist for ordinary stop orders or exchange-traded securities.
Slippage
The difference between a reference or expected order price and execution, sometimes favourable and sometimes adverse. A stop triggered during a gap can be executed far beyond its nominal threshold.
Price impact
A change in execution prices caused partly by the size and urgency of the order itself. It rises when available depth is thin; an order that looks small against daily volume may still be large at a particular moment.
Quick answer: which trading order should be used?
No order type is universally best. A market order prioritises immediate execution and gives up control of the final price. A limit order controls the worst permissible price but may never execute. A traditional stop is a conditional activation instruction rather than insurance against loss; when it triggers, the resulting market order can fill well beyond the stop level. A stop-limit order controls the price but risks retaining the exposure if no eligible match appears.
Worked example: market order versus limit order
Imagine a hypothetical stock with 100 shares offered at £50.10, another 150 at £50.20 and 500 at £50.35. A market purchase of 200 shares could take the first 100 at £50.10 and the next 100 at £50.20, giving an average execution price of £50.15 before fees. A single displayed offer of £50.10 was not sufficient to fill the entire purchase at that price. If the trader instead enters a buy limit for 200 shares at £50.10, the order cannot voluntarily pay £50.20, but it may fill only 100 shares or none as prices and available size change.
The illustration assumes that those quantities remain available, that there are no additional hidden instructions and that an incoming order receives access to those prices. In reality, quotes can change between observation and execution, other orders can have priority, and a platform may route to multiple venues. Market orders are particularly exposed to changing liquidity during announcements, market opens and sharp price gaps.
Worked example: protective stops and gaps
Consider an illustrative long share position acquired at £100 with a conventional sell stop triggered at £95. Overnight, material news leads to the next executable bid appearing at £88. If the stop activates as specified, it can become a market sell and execute near the available £88 price. The loss is then approximately £12 per share before costs, not the £5 that might have been expected from the stop setting. A sell stop-limit with a limit of £94 may avoid a sale below £94, but the position might remain open and continue losing value if no buyers are willing to pay that price.
A trader cannot obtain all three properties—guaranteed execution, guaranteed maximum loss and no additional cost—from an ordinary order type. Some specialist guaranteed-stop products have different contractual protection, and those must be checked separately. Stop levels are therefore useful instructions, not complete portfolio risk-control systems.
How time-in-force changes the outcome
Two otherwise identical limit orders can behave differently because one expires at the end of the session while another remains active until cancelled or until a provider-specific expiry date. An immediate-or-cancel purchase may fill 40 shares of a requested 100 and cancel the other 60, while a fill-or-kill request for 100 shares would normally execute none unless all 100 were immediately available. An all-or-none condition might wait for a complete fill if the venue supports it.
This distinction matters whenever residual exposure creates an operational problem, for example hedging an existing position or transacting in a multi-leg strategy. A partially executed hedge can leave the original risk only partly offset. A complete fill at any price, however, may be worse than waiting. The trader must identify which failure outcome is acceptable before choosing the instruction.
Conditional orders are not identical across markets
Exchange-traded shares, listed futures, OTC foreign-exchange platforms and cryptocurrency exchanges do not necessarily support the same order names. A stop may activate from the last traded price on one platform, the bid or ask on another, and a derived mark price on a third. The available time-in-force settings, extended-hours behaviour, auction eligibility and cancellation rules also differ.
Some brokers hold certain conditional instructions on their own systems rather than directly on the exchange. Broker outages, market suspensions, disconnections, liquidity shortages and trading halts can affect outcomes. Read the product and venue terms before treating a platform label as a universal market definition.
Order execution checklist
Identify the exact instrument, trading venue, order side and position size. Decide whether price certainty or execution probability matters more. Check displayed depth rather than only the best price; specify a reasonable maximum price concession if using a marketable limit. Verify time in force, trigger source, extended-hours settings, linkage between exits and the handling of partially filled quantities.
After execution, compare the actual fill report with the instruction: quantity, venue, time, gross price and total fees. Include rejected and cancelled instructions when reviewing execution quality. Consistent record-keeping can reveal whether execution assumptions made during analysis were achievable in practice.
Common order-type mistakes
Placing a buy limit above the current ask usually makes it marketable, rather than assuring a discount. Assuming an order will fill merely because a candle’s high or low crossed a level ignores quote availability and queue priority. Entering simultaneous independent stop and profit orders without a reliable linkage can leave an unintended short position after the original holding is closed. Treating a guaranteed stop as a universal exchange feature is also incorrect.
Another error is comparing quoted prices without transaction size. A share may show a narrow top-of-book spread while liquidity for a larger instruction is much thinner. A limit order can avoid paying more than its limit but does not stop adverse selection if it fills just before negative news. Choosing an order type requires a broader picture of liquidity, urgency and risk, not only a preference for one label.
Explore related glossary guides
Definitions are most useful when connected to neighbouring concepts. See Trading Glossary A–Z, Trading Costs, Market Data, Trading Risk Management for complementary market terms, risk considerations and examples.
Frequently asked questions
Are limit orders safer than market orders?
They offer more control over permissible execution price, but they can fail to execute. For a protective exit in a falling market, non-execution may expose the holder to additional losses. Safety depends on the specific objective and which risk matters more.
Does a stop-loss guarantee the maximum loss?
No. Ordinary stop orders trigger an execution instruction, often a market order. Gaps, halts and thin order books can produce fills below a sell-stop trigger or above a buy-stop trigger.
What does ‘good till cancelled’ really mean?
It means the order remains active within platform rules until filled, cancelled or automatically expired. Brokers may impose their own maximum lifetimes, and corporate actions can lead to cancellation or price adjustment.
Can a trading order be partly filled?
Yes. The quantity available at eligible prices and the time-in-force setting determine whether partial execution is permitted. A partial fill requires recalculating the remaining position and any linked protective instructions.
Is a market-on-close order executed at the last displayed quote?
Not necessarily. Closing auctions determine an auction price under exchange rules, which can differ from the final continuous-trading quote. Auction participation is governed by submission deadlines and venue-specific restrictions.
Related reading
Continue with Trading Mechanics Explained, Market Liquidity, Depth and Slippage and Stop-Loss Orders and Exits.
Sources and product rules
For investor education, consult the SEC investor bulletin on stop and trailing-stop orders and the Investor.gov glossary. Check the current order-type specifications from the broker or trading venue before using a feature.
Important notice: General financial education only. This guide is not a recommendation to trade or personalised advice. Every order type carries risks and no fill or trading outcome is assured.