Definition of Beta
Beta is a measure of a mutual fund or stock's volatility (sensitivity to price movements) relative to its benchmark market index. A beta of 1 means the fund moves exactly in line with the market. A beta greater than 1 means it is more volatile (amplifies market moves), and a beta less than 1 means it is less volatile (dampens market moves).
Example: A small cap fund with a beta of 1.5 would typically rise 15% when the market rises 10%, but also fall 15% when the market falls 10%. A balanced fund with a beta of 0.7 would rise 7% when the market rises 10%, offering more stability.
Beta is useful for understanding a fund's risk profile relative to the market. Aggressive growth investors may prefer high-beta funds; conservative investors near retirement should prefer low-beta funds. Beta alone doesn't tell the full story — a fund can have high beta but also high alpha, meaning it takes more risk but generates proportionally higher returns.