Bid-Ask Spread

Difference between the highest buy price and lowest sell price.

The bid-ask spread is the difference between the highest price a buyer is willing to pay for an asset (the bid) and the lowest price a seller is willing to accept (the ask). It represents the immediate cost of trading a security and serves as a key measure of market liquidity. In highly liquid markets, specialized market makers continuously quote both bid and ask prices to facilitate smooth trading. The spread is determined by supply and demand, trading volume, and overall market volatility. For highly liquid assets like major blue-chip stocks, the spread is often just a penny or two. For thinly traded assets, such as micro-cap stocks or certain corporate bonds, the spread can be much wider because finding a counterparty is more difficult and carries higher risk for market makers. Investors care about the bid-ask spread because it acts as an implicit transaction cost. When you buy an asset at the ask price and immediately sell it at the bid price, you lose the value of the spread. A narrow spread indicates high liquidity and lower transaction costs, while a wide spread suggests lower liquidity and higher trading costs. Retail investors can manage this cost by using limit orders instead of market orders, which allows them to specify the maximum price they are willing to pay or the minimum they are willing to accept.

Company XYZ stock has a current bid price of $50.00 and an ask price of $50.05. The bid-ask spread is calculated as $50.05 - $50.00 = $0.05. If an investor buys 100 shares at the ask price of $50.05 ($5,005 total) and immediately sells them at the bid price of $50.00 ($5,000 total), they incur an immediate transaction cost of $5.00 due to the spread.