How beta works
Beta measures how much an asset moves relative to the overall market. A beta of 1.0 means it tends to move in line with the market; 1.5 means it swings 50% more in both directions; 0.5 means it moves half as much. Beta is the standard gauge of an asset’s market risk, the part of its volatility that comes from the market itself rather than from anything specific to the company.
Worked example
The market rises 10%. A stock with a beta of 1.5 would be expected to rise about 15%; a stock with a beta of 0.6 about 6%. When the market falls 10%, the same relationships hold in reverse: the high-beta stock drops about 15%, the low-beta one about 6%. High beta amplifies both the gains and the drawdowns.
Why beta shapes a portfolio
Beta tells you how a holding behaves in a market move, so you can build a portfolio with the volatility you actually want. A book stuffed with high-beta names will soar and crater far more than the index. On Volity you can balance high-beta growth exposure with lower-beta defensives, and size positions by their beta so one volatile name does not dominate your risk.
Why it matters
Beta is the cleanest read on how much market risk you are carrying, and ignoring it means being surprised by how hard your portfolio falls in a correction. Use it to set portfolio-level volatility deliberately. Related: alpha and volatility.
Learn more in our stocks trading guide.
