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Order type mental model

Price control vs execution control

Every order answers two questions: when should the order become active, and how much price control do you want once it is active?

Educational examples only, using fictional prices. Broker trigger rules and available order types can vary, especially in fast or volatile markets.

Quick map More control usually means less certainty of a fill
Order types plotted by price control and execution certainty Market orders have high execution likelihood and low price control; limit orders have high price control and lower execution certainty. Execution likelihood Price control Lower Higher Lower Higher Market fast, no price cap Limit price cap, may wait Stop trigger, then market Stop limit trigger, then limit Less price control More price control

The five types in one screen

Think of the stop price as an activation switch. Think of the limit price as a fence around the worst acceptable execution price.

Now Market

Send it now. The broker seeks the best available price when the order reaches the market. You prioritize speed over exact price.

Fence Limit

Execute only at your limit or better. Buy limits fill at or below the limit; sell limits fill at or above the limit.

Switch Stop

Wait for the stop price. Once triggered, it becomes a market order, so execution price can differ from the stop.

Switch + fence Stop limit

Wait for the stop price. Once triggered, it becomes a limit order. Price is controlled, but execution is not guaranteed.

Moving switch Trailing stop

The stop follows favorable price movement by a fixed amount or percentage, then triggers a market order on a retrace.

Direction cheat sheet

These are the common placements when the current price is near $100. A marketable limit may execute immediately if it crosses the current quote.

Goal Typical order Price placement What you are controlling Main risk
Buy right away Market buy No fixed price Speed Final price can be higher than expected
Buy only if cheaper Buy limit At or below current price, such as $98.50 Maximum buy price Price may never fall enough to fill
Buy a breakout Buy stop Above current price, such as $104.00 Activation point Once triggered, final price can be higher
Sell only if higher Sell limit At or above current price, such as $103.00 Minimum sell price Price may never rise enough to fill
Sell if price breaks down Sell stop Below current price, such as $96.00 Activation point Once triggered, final price can be lower
Sell with a floor after trigger Sell stop limit Stop $96.00, limit $95.50 Trigger plus minimum sell price May not fill if price gaps below the limit

Concrete examples

The examples use one fictional stock, XYZ, trading around $100. The charts show the part of the order that matters most.

1. Market order: “Get me filled now”

Current quote: bid $100.00, ask $100.05. You submit a market buy for 100 shares.

1 Order arrives. The broker seeks the best available ask price at that moment.
2 Likely fill. You might buy at $100.05 if enough shares are available there.
3 Fast market risk. If the ask moves before the order fills, the execution might be $100.12 or $100.20.
Order book snapshot Best available price can move
Market order execution example A buy market order consumes the best available ask price and can execute at higher prices if the quote moves. Lower price Higher price $100.00 Bid $100.05 Ask Market buy fills at ask side Ask can jump
Bid side Ask side Immediate execution zone

2. Limit order: “Only at my price or better”

You want to buy XYZ, but only if it comes down to $98.50. You place a buy limit at $98.50.

1 Buy limit rule. It can fill at $98.50 or lower. It will not fill above $98.50.
2 Partial/no fill risk. The price can touch your limit without enough shares being available for your full order.
3 Sell mirror. A sell limit at $103.00 fills only at $103.00 or higher.
Buy limit and sell limit Horizontal lines are price fences
Limit order price path example A buy limit fills at or below the limit line and a sell limit fills at or above the limit line. Buy limit $98.50 fills here or lower Sell limit $103 fills here or higher $103 $98.50 Time
Buy limit fill zone Sell limit fill zone

3. Stop order: “Trigger, then market”

You own XYZ at $100 and place a sell stop at $96.00. If XYZ trades at or below $96, the stop triggers and becomes a market sell.

1 Stop is inactive first. It waits below the current price.
2 Trade through $96. The order becomes a market order.
3 Execution can slip. If the market drops quickly, the sale might fill at $95.40, $94.80, or another available bid.
Sell stop Stop price is a trigger, not a guaranteed fill
Sell stop trigger and slippage example A price path falls through a stop price at 96 dollars and the market fill occurs lower. Stop $96 market order starts Fill $95.40 example slippage $96 Time
Price path Trigger line

4. Stop limit: “Trigger, then protect my price”

You own XYZ at $100 and enter a sell stop limit: stop $96.00, limit $95.50.

1 At $96. The stop triggers and creates a sell limit order.
2 Limit fence. The sell order can execute only at $95.50 or higher.
3 Gap risk. If the market falls straight to $94.75 and does not rebound, the order may not fill.
Sell stop limit Price control can leave you unfilled
Sell stop limit example with no fill The stock crosses the stop price and gaps below the limit price, leaving the sell limit unfilled. Stop $96 activates limit Limit $95.50 sell only here or higher No fill price too low $96 $95.50 Time
Allowed sell zone Too low to fill

5. Trailing stop: “Follow the move, then exit on a retrace”

You own XYZ at $100 and place a sell trailing stop with a $3.00 trail. The stop starts at $97.00.

1 Price rises to $105. The stop ratchets up to $102.
2 Price falls. The stop stays at $102; it does not move down.
3 Retrace hits $102. The trailing stop triggers and submits a market sell.
Sell trailing stop Stop ratchets up, then freezes
Sell trailing stop example The price rises, the trailing stop rises below it, then the price falls into the stop and triggers a market sell. High $105 trail now $102 Start stop $97 $100 minus $3 Trigger $102 market sell starts Time
Bid price path Trailing stop line

6. Buy-side mirror: stop and trailing stop

For buy orders, the logic flips. Buy stops sit above the current price. Buy trailing stops sit a fixed amount above the ask and can move down when the ask falls.

1 Buy stop example. Current price $100, buy stop $104. If the stock trades at or above $104, it becomes a market buy.
2 Buy stop limit example. Stop $104, limit $104.50. It can fill at $104.50 or lower after the stop triggers.
3 Buy trailing stop example. Trail $3 above the ask. If ask falls from $100 to $96, the stop falls from $103 to $99; if ask rebounds to $99, it triggers.
Buy trailing stop Stop ratchets down, then freezes
Buy trailing stop example The ask price falls, the trailing stop follows above it, and then the ask rises into the stop. Low ask $96 trail now $99 Start stop $103 $100 plus $3 Trigger $99 market buy starts Time
Ask price path Trailing stop line

Rules that prevent confusion

Most mistakes come from mixing up activation, execution, and price guarantees.

Market orders do not guarantee the price. They seek immediate execution at the best available prices when they reach the marketplace.
Limit orders do not guarantee execution. They guarantee your price or better if they execute, but the market may never offer your price.
Stop price is not the same as fill price. A regular stop becomes a market order after the trigger, so slippage is possible.
Stop-limit adds a fill-or-no-fill tradeoff. The limit protects the worst acceptable price, but the order can sit unfilled after a gap.
Trailing stops only move in your favor. Sell trailing stops move up as bid rises. Buy trailing stops move down as ask falls.
Broker details matter. Some brokers or venues use different trigger rules for stop and trailing orders, so check the order ticket.