Investors buy or sell securities by issuing an order to a trading venue. The venue can be an online brokerage platform like NBDB or an individual licensed broker. An order is an instruction to buy or sell a security, such as a stock, ETF, or option at a specific price or when certain conditions are met.
Understanding the stock order process is critical to online trading and the self-directed investing journey. Choosing the right order type can help manage risk, secure better pricing, and ensure that trades align with an investor’s strategy and goals.
Understanding the different types of orders in stock trading
There are three primary types of stock orders: 1
- Market orders
- Limit orders
- Stop orders
A market order allows investors to buy and sell stocks and ETFs at posted prices. In contrast, limit and stop orders provide more control by allowing investors to set a predefined price for buying or selling.
Since financial markets can be volatile, trading orders can help investors automate part of the trading process and execute trades strategically.
What is a market order?
A market order is the simplest type of order. It instructs the broker to buy or sell a security immediately at the best available price.
As long as the market is open, market orders are typically executed right away. If you place a market order outside of trading hours, the order will be executed at the opening of the market on the following trading day and at the new, current bid/ask price.
With market orders, investors don't control the exact price at which the trade is executed. The difference between the security’s last quoted bid/ask price and the price at which the order is filled is known as slippage. This means there will typically be a discrepancy in the price between when the order is placed and when the order is executed. 2
Slippage tends to be more significant with fast-moving markets, where stock prices change quickly, and with less liquid stocks, where the last trade may have happened minutes or hours earlier. 3

However, under normal market conditions and during regular trading hours (9:30 am to 4:00 pm EST), the execution price will usually be close to the stock's current bid or ask price.
You might consider a market order when:
- Speed is a priority - If your goal is to execute a trade quickly and you are not concerned with obtaining a specific price.
- The security is highly liquid - Heavily traded stocks and ETFs typically experience minimal price slippage.
Risks of placing a market order when markets are closed
While market orders offer speed and simplicity, there are risks when placing them after market hours:
- After-hour market behavior- Security prices may not reflect real-time news, earnings reports, or other events that could affect the price.
- Price gaps - Overnight market changes can lead to price differences when the market reopens. This phenomenon is known as a gap. A market order placed when the market is closed will be executed when markets reopen and trading resumes. This can result in a significantly different price than expected.
- Low-volume stocks - Certain listed companies have very low daily trading volumes. Thinly traded stocks may experience large price swings with a single order. A limit order may be a better choice in such cases.
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Limited liquidity - If funds are limited, a limit order is
preferable to avoid purchases beyond the budget.
What is a limit order?
A limit order allows investors to buy or sell a security at a specific price or better. Unlike market orders, which execute immediately at the best available price, limit orders will only be executed if the price meets or is more favorable than the investor’s predefined conditions.
- Buy limit order – Executes at or below the specified price.
- Sell limit order – Executes at or above the specified price.
If the security does not reach the target price, the order remains unfilled. A limit order can be valid for 1 day or multiple days (at NBDB it can be placed up to 60 days out).
When to use a limit order?
Choosing between a market or limit order depends on your primary concerns: Is it price, trading quickly, or missing out on a trade? A limit order usually results in a better price than a market order, but if the security doesn't reach the predetermined price, the order purchase or sale will not convert into a trade.
- Price control is important – Limit orders help investors avoid overpaying when buying or selling too low.
- Trading illiquid securities – Some stocks have wider bid-ask spreads, making price control more critical.
While limit orders provide price protection, they do not guarantee execution. If the market price does not reach the limit price, the trade will not occur.
How to place a buy order and a buy limit order
What is a buy limit order?
A buy limit order ensures that a security is purchased at or below the specified or limit price, which is below the current price of the security.
You might consider a buy limit order when:
- You want to buy a security only at a specific price or below, such as buying a stock once it has dipped to a desired level.
- You want to buy a security at a price lower than the current market price and, therefore, avoid overpaying by specifying a maximum purchase price.
What is a sell limit order?
A sell limit order ensures that a security is sold at or above a specified price which is higher than the current price of the security.
You might consider a sell limit order if:
- You want to sell a stock once it reaches a predetermined target price, locking in profits.
What is a stop order?
A stop loss order, also referred to as a stop order or a sell stop order, is used to sell a security when its price falls to a specific level. It helps investors limit their losses or lock in part of their gains in a declining market.
Once the stop price is reached, the stop order converts into a market order to sell, and executes when the market price reaches the predetermined stop price. Investors use stop loss orders to limit losses and secure the gains they may have generated if the share price decreases.
You might consider a stop loss order when:
- You want to limit losses – A stop-loss order automatically sells a position to reduce potential losses or downside risk as part of an exit strategy.
- You want to protect profits – Investors use stop orders to protect gains from a rising stock before a downturn. It is a way to manage risk when markets become volatile.
How to place a stop loss order
What is a buy stop order?
A buy stop order triggers a purchase when the stock price reaches a specified level that is typically above the current market price. The buy stop order will be filled at the next available price on the market.
Investors who are short selling will often use buy stop orders to protect and hedge against the risk that the stocks that they are shorting will go up rather than down in value. If the short seller feels that there is a risk that they can't buy back the shares at a lower price, they can at least limit their losses by using a buy stop order.
Consider a buy stop order if you want to buy after a stock breaks above a resistance level to capture upward momentum, or if you need to cover a short sale, reducing the risk of significant losses if the stock price rises.
Understanding the differences between market, limit, and stop orders is fundamental to developing and executing a sound trading strategy that aligns with your investment goals. Each order type serves a specific purpose, and selecting the right one depends on factors like price control, timing, and risk management. By selecting the right order type at the right time, investors can navigate the markets more effectively and make more considered and informed investment decisions.
Further reading
Here are some articles and tools available on the NBDB website that you can consult to learn more and guide you on your self-directed investing journey:
- How to start investing: A guide for beginners
- Protect your gains or limit your losses while on vacation
- What is a buy stop order?
- Trading Central
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