INSIDE THE MARKET · CHAPTER 02
From Order to Trade
Follow an instruction from the learner or institution through order creation, routing, matching, execution, partial filling and cancellation.
Pressing Buy begins a process
A submitted instruction, an active order and a completed trade are different events.
A decision becomes an instruction. The instruction becomes an order with defined conditions. A broker or dealer handles it, and an execution venue or counterparty may match it with compatible interest. Only when buyer and seller agree on executable terms does a trade occur. The chart records the resulting transaction, not every intention that failed to execute.
Four words that should not be confused
An instruction tells a broker or dealer what the customer wants.
An instruction tells a broker or dealer what the customer wants. An order expresses executable conditions, such as side, quantity and price restriction. A quote displays or supplies a price at which someone is prepared to trade, subject to its size and market rules. A trade is a completed match. A quote may change without a trade. An order may wait without executing. A trade can fill only part of a larger order.
Trade now, accept the available price
A market order prioritises execution, not price certainty.
A market order seeks prompt execution against available opposing interest. It does not guarantee one exact execution price. If the available quantity at the best price is smaller than the order, the remainder may execute at less favourable prices. A fast or thin market can therefore produce a meaningful difference between the price visible when the order was sent and the average price received.
Set a boundary and accept the wait
A limit order provides price control but not an execution guarantee.
A buy limit order sets the highest price the buyer will accept. A sell limit order sets the lowest price the seller will accept. The boundary protects the learner from executing beyond the limit, but the order may receive no fill or only a partial fill. Reaching the displayed price does not always guarantee execution because other orders may be ahead, the quotation may be elsewhere, or available interest may disappear.
The trigger price is not the final fill
Trigger, activation and execution are separate moments.
A stop order is conditional. When the specified trigger is reached under the applicable broker or venue rules, a stop order becomes an executable market order. A stop-limit order instead becomes a limit order. The ordinary stop may execute away from its trigger during a gap or fast move. The stop-limit controls the permitted price but may remain unfilled.
Your order may have several destinations
The visible market and the route taken by one order are related, but not identical.
In US equities, a broker may route an order to an exchange, an electronic execution system, a market maker or an internal execution arrangement. Routing considers available prices, execution probability, speed, size and the broker's execution obligations and arrangements. The venue first receiving an order is not necessarily the venue that displayed the chart price the learner saw.
Compatible orders still need priority
Queue position is governed locally; there is no universal queue for all trading everywhere.
An order book ranks buying and selling interest according to the rules of that venue. Price usually matters first: a better price receives priority. At the same price, time priority is common, although allocation methods differ between markets and order types. An order arriving later may therefore wait behind earlier interest at the same price. Priority on one venue does not automatically create priority across every venue.
A trade can arrive in pieces
An order is the request; fills are the completed pieces.
A large order may match several opposing orders, at one or several prices. Each match is a fill. Together, the fills determine the completed quantity and average execution price. If insufficient opposing interest is available, part of the order can remain active, be rerouted or be cancelled according to its instructions.
The book is not a promise
Visible liquidity is conditional until it actually trades.
Unexecuted orders can often be cancelled or modified. A modification may lose queue priority, depending on the venue and what changed. Displayed interest therefore represents current willingness, not a permanent commitment to remain available while price approaches. Some cancellations are routine risk management; deceptive order placement is a separate regulatory question that requires evidence of conduct and intent.
How long should the order remain active?
Price is only one part of an order contract.
Time-in-force tells the handler how long or under what conditions an order may remain available. Examples include day orders, good-till-cancelled instructions, immediate-or-cancel orders and fill-or-kill instructions. Available choices and exact definitions depend on the broker, venue and product. The same price and quantity can behave differently when the time instruction changes.
Not every trade enters a central exchange book
Order language can be familiar while the execution structure differs.
Spot Forex is primarily an over-the-counter market. A customer may receive a stream or requested quote from a dealer or platform. The dealer may match the trade internally, retain the exposure temporarily or hedge through other dealers and venues. The customer still chooses whether to transact, but the route is a network rather than one universal central order book.
Execution detail disappears into the bar
Do not use a candle to answer a question that requires order-level evidence.
An OHLCV candle does not show every submitted, cancelled or rejected order. It does not reveal queue position, route, partial-fill history or the reason behind a trade. It records a compressed price outcome—and, for the certified equity data, aggregated share volume. To study execution mechanics directly, researchers need more granular quote, trade, order or broker records.