What Happens When You Place an Order

Scope. This article follows an order from instruction to settled ownership and names the parties and the costs along the way. It supplies no guidance on what to buy, how much, or when, and names no broker, venue or platform. Illustrative prices are small non-canonical figures used only to make the arithmetic legible. Jurisdiction: United States market structure, checked 14 August 2026; other markets differ in venue structure and settlement timing.

The instruction leaves the broker, travels to a place where a counterparty is found, is matched against a specific order from a specific person or firm, and then takes a further period to become recorded ownership.

Understanding that chain matters for one practical reason: costs and failures occur at each link, and most of them are invisible on the confirmation screen.

The chain, in order

1. The instruction. A reader specifies a security, a direction, a quantity, an order type and a duration. Those last two are the parts most people leave on their defaults, and they determine what actually happens more than anything else in the instruction.

2. The broker receives it. The broker is an agent — it does not own the security a reader is buying and is not, in the ordinary case, the counterparty. Its obligation is to seek a favourable outcome for the order, a duty covered in Pillar 30.

3. Routing. The broker decides where to send the order. There is no single place where trading happens — a market is a set of competing venues, and the choice among them is made by the broker rather than the reader. That decision is the subject of the article on venues and routing.

4. Matching. At the venue, the order is matched against opposing orders under published priority rules. Somebody specific is on the other side — the trade does not occur against an abstraction.

5. Clearing. A clearing organisation steps between the two parties and becomes the counterparty to each, so that neither depends on the other's ability to perform.

6. Settlement. Cash and securities actually change hands. In the United States, standard settlement for equities moved to one business day after the trade — T+1 — in May 2024. The trade and the ownership are separate events on separate days, which is why a sale's proceeds and the ownership record do not update at the same moment.

The costs, and where they sit

Three costs attach to almost every order, and only one of them is usually itemised.

Commission — an explicit charge, which many brokers have reduced to nothing on ordinary equity orders. It is the most visible cost and frequently the smallest.

The spread — the difference between the price at which one can buy and the price at which one can sell at the same moment. It is not itemised anywhere, and it is paid on entry and again on exit.

Market impact — the effect of the order itself on the price, which matters when an order is large relative to what is available.

Worked example — the cost nobody is charged and everybody pays. Buying 100 shares at $40.02 and selling immediately at $39.98 costs $4.00 on a $4,000 position — 0.10% — with no commission charged and nothing itemised. In the wider market the identical round trip costs $50.00, or 1.25%, which is more than twelve times as much for the same instruction on the same quantity. The arithmetic compounds with activity in the way the article on momentum sets out: at twenty-six round trips a year the narrow case costs 2.6% of capital annually and the wide case 32.5%. MarketClue publishes no threshold for an acceptable spread and does not characterise any market as narrow or wide — the point is that the cost exists, is unitemised, and varies by more than an order of magnitude between securities. Figures are illustrative and describe no actual security.

Who is on the other side

Most orders from individuals do not meet another individual. The counterparty is typically a firm that continuously offers to buy and to sell, earning the spread for providing immediacy — a service with a real cost, since the firm takes on inventory it may not want.

That relationship is symmetrical and worth stating plainly. A reader who wants to trade immediately is buying immediacy from someone, and the spread is the price. A reader willing to wait can supply immediacy instead of consuming it, which is what the article on limit orders is about — and this portal describes that difference without suggesting which side of it anyone should be on.