™Stock Market University · Market Foundations
What Happens When You Buy a Stock?
Understand the essentials.
Follow a stock order from your screen through routing, matching, execution and settlement.
The idea to understand
Trace an order from instruction to routing, execution, clearing and settlement without confusing a quote with a guaranteed fill.
The explanation
The essentials, explained.
Follow the idea, then work through an example. Pause at the self-check whenever you are ready.
1. You submit an order
Your order specifies the security, quantity, side and order type. A market order prioritizes execution; a limit order sets the worst price you are willing to accept.
2. Your broker routes it
The broker performs required checks and routes the order to an exchange, market maker or other venue under its execution policies.
3. The order meets liquidity
At the venue, the order can match against a compatible order. A fill may happen at once, in pieces or not at all, depending on price, size and available liquidity.
4. Execution and settlement
The broker reports the execution to you. Clearing and settlement processes then finalize the exchange of securities and cash. Most covered U.S. securities trades use T+1, the next eligible business day, rather than the next calendar day.
Price control versus execution
Order type changes the trade-off. A market order emphasizes prompt execution but does not guarantee price. A limit order sets a worst acceptable price but may remain unfilled. Liquidity, volatility, spread and order size all matter when deciding which risk is more important.
What to check after the fill
Review the execution price, quantity and whether the order filled in one piece or several. Then distinguish execution from settlement: the trade may appear in the account immediately even though securities and cash still move through clearing and settlement processes afterward.
Optional context & practice
Why this matters
A click, an execution and settlement are separate events. That distinction explains partial fills, price differences and when cash and securities are exchanged.
Useful vocabulary
Market order: An order seeking prompt execution at the best available prices; the execution price is not guaranteed. Limit order: An order to buy or sell only at a specified price or better; execution is not guaranteed. Settlement: The process that finalizes the exchange of securities and cash after a trade.
Execution and settlement answer different questions
A fill establishes an executed quantity and price. Settlement completes the contractual transfer. Most covered U.S. securities trades use T+1: one business day after the trade, excluding applicable holidays. That does not make a quote an execution or eliminate settlement failures. Cash-account payment rules and a broker's available-to-trade display still need to be understood.
Try it with a hypothetical example
Read a broker confirmation and settlement policy. Identify order time, fill price, quantity, fees and settlement date; compare trading days with calendar days.
A question to think through
A covered U.S. stock trade executes on Friday and Monday is a settlement holiday. What is the ordinary scheduled settlement day?
Compare your reasoning
Tuesday, the next eligible business day. This assumes ordinary T+1 treatment and no other exception.
A moment to reflect · optional
What does a market order prioritize?
Think through your answer, then compare it with the explanation.
Reveal the explanation
Prompt execution at the best prices then available; it does not guarantee a particular execution price.
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Sources & editorial notes
Reviewed 2026-10-13 · My Market Book editorial team. Examples are hypothetical unless identified as historical. General education, not a personal investment recommendation. Next scheduled review: 2027-04-11, or earlier after a material change. Conceptual and evergreen.