Which type of order allows an investor to buy or sell a stock at the best available price?

A market order is an instruction to buy or sell a stock immediately at the best available price in the market. This type of order is executed quickly, making it ideal for investors who want to enter or exit a position without delay. The primary goal of a market order is to prioritize speed of execution over price, ensuring that the investor can transact almost instantly.

When using a market order, the investor does not specify the price at which to buy or sell; they accept the current market price instead. This is especially useful in fast-moving markets where stock prices can fluctuate rapidly. While there may be some uncertainty regarding the exact price at which the order will be filled, market orders are generally filled promptly, allowing investors to respond swiftly to market conditions.

In contrast, other order types such as limit orders require specified price conditions, making them less suitable for immediate transactions. A stop order is designed to trigger a market order once a certain price threshold is reached, and an all-or-none order stipulates that the transaction must be completed in full or not at all. Each of these options serves different purposes, but a market order is specifically tailored for executing trades quickly at the best available price.