Order Types Explained for the SIE Exam: Market, Limit, Stop & Stop-Limit

Investors use different order types to control how a trade fills — and the SIE expects you to know four cold: market, limit, stop, and stop-limit. The one-line version: a market order guarantees execution but not price, a limit order guarantees price but not execution, a stop order is a trigger that becomes a market order once a set price is hit, and a stop-limit becomes a limit order once triggered — adding price protection but risking no fill.

Order handling sits inside “Understanding Trading, Customer Accounts and Prohibited Activities,” the second-largest SIE section at 31% of the scored exam (75 scored questions in total). Throughout, picture one stock trading at $50 and watch where each order goes.

Market orders

A market order tells your broker to buy or sell immediately at the best available price. It fills as soon as it reaches the exchange, matching the current bid or ask. Because it has no price restriction, a market order has the highest chance of execution — the trade happens right away. What it does not do is guarantee a price. In fast-moving markets the execution price can “slip” past the quoted price, so you might pay a little more or receive a little less than expected. And an order entered while the market is closed fills at the next open, where overnight news can move the price.

The takeaway: a market order guarantees execution, not price. Use one when getting the trade done matters more than the exact price.

Limit orders

A limit order sets a price boundary. You specify a limit price, and the order fills only if the market reaches that price or better — so a limit order guarantees the price (or better), not execution.

• Buy limit: entered below the current market price; it fills only when the stock falls to your limit or lower. Stock at $50, buy limit at $48 → you’ll never pay more than $48, but if it never drops that far, you don’t fill.
• Sell limit: entered above the current market price; it fills only when the stock rises to your limit or higher. Stock at $50, sell limit at $52 → you’ll get at least $52, but only if it climbs there.

Because limit orders rest in the order book until reached, they risk never filling — and even when the price is hit, you can get a partial fill if not enough shares are available at your price.

The takeaway: a limit order guarantees price, not execution. Use one when price control matters more than immediate execution.

Stop orders

A stop order (often a “stop-loss”) has a trigger price. When the stock trades at or through the stop, the order is “elected” and converts into a market order, then executes immediately at the next available price. Because it becomes a market order, a stop does not guarantee price — only that the trade happens once the stop is hit.

• Sell stop: placed below the current market to protect a long position. Long at $50 with a sell stop at $47 → if the stock falls to $47, it fires and sells at the next price (possibly $47, possibly lower if the market keeps dropping).
• Buy stop: placed above the current market to protect a short position. Short at $50 with a buy stop at $53 → if the stock rises to $53, it fires and buys to cover.

Remember the two-step process: the stop triggers first, then executes as a market order — so the fill price can differ from the stop price in a volatile market.

Stop-limit orders

A stop-limit order combines the two. You set a stop (trigger) price and a limit price. When the market hits the stop, the order activates — but as a limit order rather than a market order.

• Sell stop-limit: long at $50, stop $47, limit $46. If the stock falls to $47, the order triggers, then sells only at $46 or higher. If it slices straight through $46 without trading there, the order sits unfilled.
• Buy stop-limit: short at $50, stop $53, limit $54. If the stock rises to $53, it triggers, then buys only at $54 or lower.

The advantage is price control — you won’t pay more or accept less than your limit. The trade-off is that execution isn’t guaranteed: if the market blows past your limit without trading at it, the order may never fill.

The takeaway: a stop-limit becomes a limit order when triggered — it guarantees the limit price (or better) if filled, but not execution.

Order type is what happens on the trading side; when the trade actually settles is a separate SIE concept. For the current U.S. settlement cycle, see our T+1 settlement explainer.

The placement chart — the big SIE point

This is the part the exam loves to test, and the part students most often flip. Relative to the current market price:

• Buy limits and Sell stops go BELOW the market.
• Sell limits and Buy stops go ABOVE the market.

Two mnemonics capture it: BLiSS — Buy Limits and Sell Stops (below) — and SLoBS — Sell Limits and Buy Stops (above).

The intuition: you want to buy low, so a buy limit sits below the market; you want to sell high, so a sell limit sits above. A sell stop protects a long by triggering as the price falls, so it sits below; a buy stop protects a short by triggering as the price rises, so it sits above.

Order type	Guarantees	Placed vs. market	When triggered, becomes
Market	Execution, not price	Fills now	— (executes immediately)
Buy limit	Price (or lower), not execution	Below	— (already a limit)
Sell limit	Price (or higher), not execution	Above	— (already a limit)
Sell stop	Trigger only, then market price	Below	A market order
Buy stop	Trigger only, then market price	Above	A market order
Sell stop-limit	Limit price (or better) if filled	Below (stop)	A limit order
Buy stop-limit	Limit price (or better) if filled	Above (stop)	A limit order

Order qualifiers and durations

Beyond the type, an order carries instructions on how long it lives and how it may fill:

• Day order — expires at the end of the trading day if not filled (the default).
• Good-til-canceled (GTC) — stays working until it fills or you cancel it. Limit and stop orders can be entered day or GTC.
• Fill-or-kill (FOK) — fill the entire order immediately or cancel the whole thing.
• Immediate-or-cancel (IOC) — fill as much as possible immediately and cancel the rest (partial fills allowed).
• All-or-none (AON) — fill the entire order (no partials), but not necessarily immediately; it can keep working.
• Market-on-open / market-on-close (MOO / MOC) — execute at the day’s opening or closing price.

Exam traps to avoid

• Market guarantees execution, not price; limit guarantees price, not execution. Don’t swap them.
• A stop order becomes a MARKET order when triggered; a stop-limit becomes a LIMIT order. That single difference is why a stop-limit can go unfilled.
• Don’t flip the placement chart. Buy limits and sell stops are below the market; sell limits and buy stops are above (BLiSS / SLoBS).
• A sell stop is below the market and protects a long; a buy stop is above the market and protects a short.
• FOK vs IOC vs AON: FOK = all, now, or cancel; IOC = as much as possible now, cancel the rest; AON = all, but not necessarily now.

Once BLiSS/SLoBS and the trigger-then-market-vs-limit distinction feel automatic, test yourself with the free SIE diagnostic to see how the SIE actually frames order-type placement and stop-vs-stop-limit questions.

Frequently asked questions

What’s the difference between a market and a limit order?

A market order fills immediately at the best available price, guaranteeing execution but not the price. A limit order fills only at your specified price or better, guaranteeing the price but not that the trade happens.

What is a stop order and how does it work?

A stop order rests until the stock trades at your stop (trigger) price. At that point it “elects” and becomes a market order, executing at the next available price. It guarantees the trade occurs once triggered, but not the price you get.

What’s the difference between a stop and a stop-limit?

Both use a trigger price. A plain stop becomes a market order when triggered (execution assured, price not). A stop-limit becomes a limit order when triggered (price assured if it fills, but it may not fill if the market moves past your limit).

Where do you place a buy stop versus a buy limit?

A buy limit goes below the current market (you want to buy at a lower price). A buy stop goes above the current market (it triggers as the price rises, typically to cover a short). Same word, opposite sides of the market.

Does a limit order guarantee my trade will fill?

No. A limit order guarantees only that if it fills, it fills at your limit price or better. If the market never reaches your price — or moves through it too fast — the order can sit unfilled or fill only partially.

What does GTC mean?

Good-til-canceled: the order stays active until it executes or you cancel it, rather than expiring at the end of the day like a day order.

One hook to carry in: market = execution, limit = price, stop = trigger-then-market, stop-limit = trigger-then-limit — and BLiSS/SLoBS for where they sit. Get those two ideas down and the order-type questions on the SIE become quick points.