Markets · Explainer
Market, limit, stop: the order type is part of the trade
Choosing how to execute is a decision about which risk you are willing to accept — price risk or completion risk.
The short answer
- A market order guarantees execution, not price; a limit order the reverse.
- Stop orders convert into market orders and can fill far from the trigger.
- Spreads and depth matter more than commission for less liquid instruments.
Every trade carries two risks that cannot both be eliminated: the risk of not transacting, and the risk of transacting at a bad price. Order types are the mechanism for choosing which one you accept.
The core three
- Market order: executes immediately against the best available prices. Certain completion, uncertain price.
- Limit order: executes only at your price or better. Certain price, uncertain completion.
- Stop order: dormant until a trigger price trades, then becomes a market order — with all the price uncertainty that implies.
Where it goes wrong
Stop orders are the common trap. In a fast, thin market the trigger and the fill can be far apart, because there may be no resting bids near the stop level. A stop-limit order caps that damage but reintroduces the risk of no fill at all, which is precisely the outcome a protective stop was meant to prevent.
Auctions and after-hours
Opening and closing auctions concentrate liquidity into a single price and are often the cheapest moments to trade size. Outside regular hours, depth thins dramatically; an order that behaves predictably at midday can fill at a startling level at seven in the morning.
Sources
- Types of orders — U.S. SEC (Investor.gov)
- Trading and markets — FINRA
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