Between a market order and a limit order, the guarantee offered is not the same: a market order generally executes right away, but at a price that is not guaranteed and that can diverge from the last quoted price if the market moves quickly, according to the SEC (Investor Bulletin: Trading Basics, accessed October 17, 2026). A limit order, by contrast, offers a price guarantee but no execution guarantee. This distinction is not a technicality: it determines what you actually risk depending on the order type you choose on your platform.
What a market order actually guarantees
The SEC defines a market order as an order to buy or sell a stock executed at the best available price. It specifies that this type of order generally executes immediately, but that the execution price is not guaranteed: “A market order is an order to buy or sell a stock at the best available price. Generally, this type of order will be executed immediately. However, the price at which a market order will be executed is not guaranteed” (SEC, Investor Bulletin: Trading Basics, 2026). In practice, you get fast execution in exchange for total uncertainty about the final price, especially when the order book thins out quickly beyond the best displayed price.
What a limit order actually guarantees
A limit order works the other way around: it sets a ceiling price for a purchase or a floor price for a sale, without ever guaranteeing that the order will find a counterparty. The SEC puts it this way: “A limit order is an order to buy or sell a stock at a specific price or better. A buy limit order can only be executed at the limit price or lower, and a sell limit order can only be executed at the limit price or higher” (Investor.gov, Investor Bulletin: Understanding Order Types, July 12, 2017, accessed October 17, 2026). If the market price never touches your limit, the order simply stays pending, partially or fully unfilled.
The SEC’s numeric example: one order, two prices
To illustrate the price risk of a market order, the SEC gives a concrete example: in a fast-moving market, an order for 1,000 shares could see 500 shares execute at $3.00 and the other 500 shares execute at a higher price, for a single market order placed all at once: “In a fast-moving market, 500 shares of the order could execute at $3.00 per share and the other 500 shares execute at a higher price” (SEC, Investor Bulletin: Trading Basics, 2026). This example shows that the immediate-execution guarantee of a market order says nothing about a predictable average price, especially for a stock or instrument whose liquidity shifts quickly between two price levels.
| Order type | Price guarantee | Execution guarantee |
|---|---|---|
| Market order | No | Yes, generally immediate |
| Limit order | Yes, at the limit price or better | No |
What this changes on a WeGetFunded simulated account
On a simulated account where a drawdown threshold recalculates every day, as explained in the article on the trailing EOD drawdown at WeGetFunded, the price gap described by the SEC is not trivial: a market order filled at a worse price than expected mechanically pushes the account closer to its threshold. Conversely, a limit order protects the entry or exit price, but may never execute if the market moves away from the set limit, which leaves a position open longer than planned. The choice between the two therefore depends on what you fear most: a degraded price or a non-execution.
Frequently asked questions
Is a market order faster than a limit order?
Yes, according to the SEC a market order generally executes immediately, because it accepts the best available price unconditionally. A limit order, by contrast, can remain pending indefinitely if the market never touches the set price.
Why can the price of a market order change during execution?
Because the order consumes the available quantities at each price level in the order book: if the requested quantity exceeds what is offered at the best price, the remainder of the order executes at the next price level, as shown in the SEC’s numeric example where 500 shares out of 1,000 execute at a higher price.
Does a limit order protect against any price loss?
It only protects the set price level: a buy limit order will never execute above the limit, and a sell limit order never below it. It does not, however, guarantee any execution if that price is never reached.
Should you always prefer a limit order over a market order?
It depends on your priority: the SEC does not recommend one order type over another, it simply describes their respective guarantees. A market order suits situations where immediate execution matters most, a limit order where price control matters most, for example near a regulatory close-out threshold.