Beta is a measure of how much an investment's price tends to move relative to the broader market. A beta of 1 means the investment moves in line with the market; a beta above 1 means it's more volatile, and a beta below 1 means it's less volatile. For example, a stock with a beta of 1.5 tends to rise or fall about 50% more than the market on a given day. Investors use beta to understand the risk profile of an investment and how it might behave during market swings. A higher beta can mean higher potential returns in a bull market but steeper losses in a downturn, making it an important factor when building a portfolio that matches your risk tolerance.