The spread is the difference between the bid price (the highest price that a buyer is willing to pay for a security) and the ask price (the lowest price that a seller is willing to accept for a security). In other words, it is the gap between the prices at which a buyer is willing to buy and a seller is willing to sell a security.

The spread is an important concept in trading and is often used as a measure of liquidity in a market. A wider spread generally indicates that there is less liquidity in the market, as there may be fewer buyers and sellers willing to trade at the current prices. A narrower spread, on the other hand, may indicate that there is more liquidity in the market, as there are more buyers and sellers willing to trade at the current prices.

The spread can also be used as a measure of the costs associated with trading a particular security. For example, if the spread is wide, it may be more expensive to buy or sell the security, as the trader may have to pay a higher price to execute the trade. In contrast, if the spread is narrow, it may be cheaper to buy or sell the security, as the trader may be able to execute the trade at a lower price.

Example:

“I was considering buying some shares of XYZ stock, but when I checked the market, I saw that the spread was quite wide. The bid price was $50 per share and the ask price was $55 per share, so I decided to wait and see if the spread narrowed before making a trade.”