A limit order guarantees a price but not a fill. A market order guarantees a fill but not a price. A stop order guarantees neither until the stop price triggers it. Which one suits a given trade depends on whether execution matters more than price, or the reverse.
Market orders: the fill is certain, the price is not
The U.S. Securities and Exchange Commission’s Investor Bulletin on trading basics (SEC Pub. No. 141, dated March 2011) defines a market order as an instruction to buy or sell “at the best available price,” and says this type of order will generally execute immediately — but the execution price is not guaranteed. The bulletin’s own example: an investor places a market order to buy 1,000 shares of a stock quoted at a $3.00 offer. If other orders execute first, the SEC says, the investor’s order may fill at a higher price. In a fast-moving market, the bulletin adds, part of that same 1,000-share order could fill at $3.00 while the remaining shares fill at a higher price — one order, two different execution prices.
FINRA’s investor education page describes the same mechanism independently, noting that a market order “generally will execute at or near the current bid or ask prices” during normal trading hours, but that the investor “might not get the price you saw or were originally quoted, especially in fast-moving markets.” Two separate regulator-facing sources agree on the same trade-off: speed and certainty of execution, at the cost of price certainty.
Limit orders: the price is certain, the fill is not
A limit order flips that trade-off. The SEC’s bulletin defines it as an order to buy or sell “at a specific price or better,” and gives the example of an investor who wants to buy shares for no more than $10: a limit order at $10 will only execute if the market price is $10 or lower. FINRA’s page states the same rule from the other side — a sell limit order can be executed only at or above the limit price — and adds the cost of that protection plainly: “there’s a chance your order doesn’t get executed at all.” If the market never trades at or through the limit price while the order is active, nothing happens.
CME Group’s own futures-education course page on order types states the same principle for futures markets in one line: a limit order “cannot be filled worse than the limit price but can be filled better.” That second clause is easy to miss — a limit order is not a ceiling on how good your fill can be, only a floor (or cap) on how bad it can be.
Stop and stop-limit orders: neither is guaranteed until the trigger fires
A stop order does nothing until the market reaches a specified stop price. The SEC’s bulletin describes it as an order that, once the stop price is reached, “becomes a market order.” FINRA’s page independently corroborates this, saying the order “automatically turns into a market order and is executed as soon as possible at the current market price” once triggered. Both sources make the same warning explicit: the stop price is a trigger, not a promised execution price, and in a fast-moving market the eventual fill can land well away from the stop price.
A stop-limit order changes what happens after the trigger. The SEC’s bulletin walks through a worked example: a sell stop-limit order with a stop price of $3.00 and a limit price of $2.50 becomes an active limit order once the market trades at $3.00 — but from that point it can only fill at $2.50 or better. The bulletin’s own caution applies here too: a stop-limit order can fail to execute at all if the market moves past the limit price before the order is filled. That trade-off runs in the opposite direction from a plain stop order, which guarantees execution but not price. FINRA separately describes a variant, the trailing stop-loss order, whose stop price moves with the market by a set percentage or dollar amount rather than sitting fixed.
A fourth mechanic: capping how far a market order can slip
Retail explainers of market orders usually stop there: a market order fills immediately at whatever price is available. CME Group’s Globex documentation, in a wiki updated 20 June 2025, describes two variants that add a price boundary to that idea. A “market-limit” order fills at the best available price, and if it can only be partly filled, the unfilled remainder does not keep chasing the market — it becomes a resting limit order at that same fill price. CME’s worked example: a bid order fills 2 lots at 90025, and the remaining quantity rests on the book at 90025 rather than continuing to buy at higher prices.
A “market order with protection” goes further, defining a price range the order is allowed to fill within. In CME’s bid-side example, the best offer is 90025 and the protection allowance is 600 points, so the order cannot fill above a protection limit of 90625. The order fills 2 lots at 90025, 3 lots at 90300, and 3 lots at 90550; the next best offer, at 90675, exceeds the protection limit, so CME Globex places the unfilled remainder on the book as a limit order at 90625 rather than letting it chase the price further. CME’s offer-side example works the same way in reverse: a best bid of 90000 with 600 points of protection sets a floor of 89400, fills occur at 90000, 89900 and 89650, and the remainder rests at 89400 once the next best bid of 89300 would have breached that floor. This is, in effect, a market order with a limit order’s downside protection built in — a mechanic documented here for CME Globex futures markets, not for the U.S. equities orders described in the SEC and FINRA material above.
What crypto exchanges document, and what they don’t
Crypto exchanges publish their own order-type lists, but the level of documented detail varies sharply, and this evidence set does not let this page describe the mechanics of any of them with confidence. For Crypto.com’s exchange documentation, this page holds only the page’s headline — “Crypto.com Exchange” — and cannot confirm anything about its order types beyond that. Cboe Digital’s FIX specification lists Limit, Stop-Limit, Market and Post-Only order types, per that single document. Binance’s spot API documentation is the reference point for its own order types, but the copy of that page held for this article contains only site navigation and file metadata, not the order-type descriptions themselves — so no claim about Binance’s specific mechanics can be sourced from it.
The common misreading
One common misreading is to treat a stop price as a promised exit price. It isn’t. Both the SEC and FINRA are explicit that the stop price only triggers an order; the price at which that order then executes depends on where the market is trading at the moment it fires, which can be materially different from the stop price itself — especially, as the SEC’s bulletin notes, in a fast-moving market.
What this page does not tell you
This page cannot describe how any specific crypto exchange decides a stop price has been reached — whether it uses last-trade price, a mark price, or an index price — because none of the crypto-exchange sources held for this article include that detail: the Cboe Digital source is limited to order-type names, the Crypto.com source is limited to its headline, and the Binance source contains no body text on the subject at all. The SEC and FINRA material describes rules and norms that apply to U.S. equities brokerage accounts; it says nothing about how any crypto exchange’s rulebook governs order matching, and crypto venues are free to set their own logic. Finally, this page cannot say whether any crypto exchange offers something equivalent to CME’s protected-range market order, which caps how far a market order can slip — no crypto-exchange source reviewed here describes such a feature, so its absence in this page reflects a gap in the evidence, not a confirmed absence in the market.
Sources
Every fact above is attributed to one of these reports. Where they disagree, the article says so.
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