A trade ticket’s labels can create a false sense of precision. A price entered into a form does not always become the price at which the market trades. The US Securities and Exchange Commission’s Investor.gov guide, published 12 July 2017 explains the distinction between order instructions and executed transactions.
Market order: execution first, price second
A market order asks to trade at the best currently available price. It prioritizes getting filled; it does not promise the price of the last trade or the number on the screen when you clicked. In a market with little available volume, a large order can execute in several fills, each at a different price.
Consider a hypothetical purchase of 1,000 shares. The displayed best offer might show only 300 shares at USD 20.00; filling the remaining 700 requires available sellers at other prices. This is an invented teaching example, not live order-book data. The principle is sourced from the SEC order-types bulletin.
Limit order: price protection, not guaranteed participation
A buy limit allows execution only at its limit or better. A buy limit of USD 20 will not intentionally fill at USD 20.50, but it may never fill if enough shares are not offered at or below USD 20. A sell limit similarly specifies a minimum acceptable selling price.
The trade-off is straightforward: the tighter your price constraint, the greater the chance that a fast market moves without you. A limit order that never fills is not evidence that the broker malfunctioned; you need to examine queue priority, liquidity and conditions.
Stop orders: the most misunderstood word in the ticket
A stop order activates when a defined trigger is reached. For a typical stop-market instruction, that trigger then releases a market order. The SEC’s stop-order bulletin stresses that the trigger price is not the execution price. Gaps and fast moves can produce a worse exit than a planned stop.
For example, an investor holds a stock bought at USD 50 and places a sell stop at USD 45. If the market gaps from USD 47 to USD 42, the stop may be triggered but execute near available bids, not at USD 45. The example describes mechanism, not a prediction about any company.
A stop-limit adds a limit after the trigger. It can restrict the worst acceptable price, but now the order can remain unfilled while the market continues moving against the position. There is no free combination of fully guaranteed price and fully guaranteed execution.
Trailing stops and time instructions
Trailing stops move their trigger with favorable price changes under the broker’s rules. They do not prevent unfavorable gaps. Broker policies differ on what constitutes a trigger—last trade, bid/ask quote or another convention—so compare actual order documentation rather than relying on a generic dropdown.
Day, good-til-canceled, immediate-or-cancel and fill-or-kill instructions specify time and completion constraints, not forecasting intelligence. The SEC bulletin details how they work and warns that exact availability varies by firm.
A realistic pretrade checklist
Before submitting an order, record the security or pair, quantity, estimated notional exposure, order type, limit or stop trigger, time-in-force, whether extended hours apply, expected commission and maximum capital you are prepared to lose. Read the broker’s cancellation and margin rules.
For a forex or CFD account, establish whether the quoted price is an OTC dealer price, whether an order could be rejected, and what happens during a margin close-out. One interface may not support every instruction listed in a broker’s general help center.
Common mistakes and limits
It is incorrect to describe a stop as a guaranteed maximum loss, to assume a limit order must fill because a chart touched the level, or to equate a market order with the most recent trade print. Real execution also depends on routing, queue conditions and market rules. This explainer addresses order mechanics, not the execution quality of any broker. Pair it with position sizing and our risk warning.
