Beta measures a fund's relationship with its market: when the index moves 1%, how much is the fund expected to move? A beta of 1.0 means near-identical movement; 1.3 amplifies moves by about 30%; 0.6 means a calmer ride than the market.
The key insight is that amplification works both ways: a high-beta fund shines in rising markets and hurts more in falling ones. So high beta is neither a virtue nor a flaw in itself — it describes the fund's behaviour so you can judge its fit for you.
Beta captures only market risk — the part tied to index movement. A fund concentrated in one sector can have a moderate beta while carrying large specific risks this number never shows; read beta alongside total volatility, not instead of it.
As with alpha, beta is only meaningful against an appropriate index: a Saudi equity fund's beta is normally computed against the Saudi market index, not a global one.