Beta measures how much a fund's price tends to swing compared to the overall market. A beta of 1 means the fund generally moves in line with the market — if the market rises 10%, the fund tends to rise about 10% too. A beta above 1 means the fund is more volatile than the market, amplifying both gains and losses, while a beta below 1 means it's comparatively calmer.
For example, a fund with a beta of 1.3 could be expected to fall roughly 13% if the market fell 10%, but it could also rise about 13% during a 10% market rally. Investors who are cautious about big swings in their portfolio's value often prefer funds with a lower beta, while those chasing higher growth and comfortable with volatility may accept a higher beta. It's a useful gauge of how bumpy the ride might feel, not of quality.