The First Trade Is Executed

Reading time: 4.0-5.0 min

Event: At 8:03 a buyer submits an order to buy 5 apples at $10 per apple.

The order is recorded in the bids ledger

At this moment, the book contains three orders:

A - an ask to sell 5 apples at $10
B - a bid to buy 2 apples at $9
C - a bid to buy 5 apples at $10 the new order.

What happens

The incoming buy order A is priced at $10 which matches the existing sell order C priced at $10
The quantities also match: the buy order is for 5 apples and the sell order offers 5 apples.

Because the prices match and sufficient quantities exist on both sides, a trade can occur

At this point, no trade has been executed yet No apples have been exchanged, and nothing has been recorded in the trade tape.

Executing the Trade

5 apples are exchanged at a price of $10 per apple. At the same time:

the matched sell D , and buy E orders are removed from the book, and
the trade F is recorded in the trade tape at 8:04

This is the moment when a price is first recorded.

Reported Price

Reported prices are visible to external observers. The most recent reported price is the current market price.

The previous sections described the changes to the records resulting from this execution. This section explains what the reported price represents more generally, and what it does and does not imply about future trades.

The reported price comes from the trade tape

It appears in the records only when a trade has been recorded.

The trade tape remains as a permanent record of what happened.
The asks and bids ledgers now reflect only open orders

IMPORTANT — About Execution, Price, and Time

Execution can occur only if, at the moment an order arrives, there is an existing order on the opposite side priced so a trade can occur.
Execution is a separate event from order entry; matching evaluation determines whether execution occurs.
The trade tape contains only execution times, not the times of order placement or removal.

Although the buy order was submitted at 8:03 the trade was executed and recorded later, at 8:04

About the Reported Price

Definition

The reported price is the price of the most recent completed trade.

It appears as the latest entry in the trade tape and is visible to external observers. At any moment, this latest reported price is what is commonly referred to as the current market price.

What the Reported Price Is

The reported price is a historical fact

It records the price at which the most recent exchange of apples actually took place.

It comes entirely from the trade tape, and nowhere else.
The trade tape records completed trades only. It contains no information about:

open buy or sell orders,
quantities still available,
or the structure or state of the order book.

When a Reported Price Exists

A reported price exists only because a trade occurred

If no trade has ever occurred, no reported price is present.
If trades stop occurring, the last reported price remains visible and unchanged.
The reported price updates only when another trade is completed.

The presence of a reported price therefore tells you nothing about current activity — only that something traded at some point.

What the Reported Price Does Not Mean

The reported price does not mean that apples can currently be bought or sold at that price.

It does not mean that any buy or sell orders exist at that price.

It does not mean that the next trade will occur at that price.

And it does not serve as a starting point, reference, or anchor for future trades.

What Determines the Next Trade

The reported price plays no role in determining what trades next.

Although the trade tape contains history, the mechanics of matching and execution do not consult that history.

What can trade next depends only on:

the buy and sell orders currently written in the book, and
the order in which those orders arrived.

Only prices and quantities present in the book at the moment an order arrives matter.

If no buy order and sell order overlap on price, no trade will occur — even if one or many reported prices exist in the trade tape.

In short:

The reported price tells you what did trade.
The book tells you what can trade.
The latest reported price is a record not a mechanism.

Trade tape:  $10  (last completed trade)
Book:        no orders at $10

The reported price remains unchanged until another trade occurs, regardless of whether any orders exist in the book at that price.

What Charts Represent

Charts in trading software visualize reported prices — records of trades that have already completed

Because the reported price is a historical record, charts are necessarily retrospective: they show what has already happened, not what will happen next.

Humans are exceptionally good at detecting patterns in historical records. When prices change repeatedly over time, the resulting sequences can appear structured, directional, or repetitive.

That appearance does not mean that price itself has memory or influence.

What can influence future trades are the orders that exist in the book at the moment of order arrival. When many orders are placed or removed around similar prices over time, the resulting executions can leave visible traces in the trade tape.

Charts display those traces.

The mistake is not looking at charts. The mistake is treating the charted price as the cause of future trades rather than as the record of past ones.

In this tutorial, charts are treated as descriptions of history, not as drivers of market behavior.