Volatility
Standard deviation of a fund's returns, annualised — the most widely used measure of total return dispersion and investor discomfort.
Volatility is the foundational risk metric in fund analysis. It measures how much a fund's returns have varied around their average — both up and down. A fund with high volatility delivers returns that swing widely from period to period; a low-volatility fund delivers more predictable, stable outcomes. Understanding volatility before investing helps you avoid being surprised by the ride.
What it measures
Volatility is the annualised standard deviation of periodic returns. It captures the total dispersion of returns — both gains above average and losses below. A fund earning 12% CAGR with 8% annual volatility is very different from one earning 12% with 22% volatility; the second fund will test investor nerves far more along the way.
How it is computed
MintByte computes volatility from monthly returns over a 3-year window:
- Compute monthly return
R_ifor each of the 36 months - Compute mean monthly return
R̄ - Monthly standard deviation:
σ_monthly = √[ Σ(R_i − R̄)² / (n−1) ] - Annualise:
σ_annual = σ_monthly × √12
σ_annual = √12 × √[ Σ(R_i − R̄)² / (n−1) ]
The √12 scaling assumes returns are independent across months (no autocorrelation), a standard approximation.
Example: A balanced hybrid fund has 36 monthly returns with mean 1.0%/month and standard deviation 2.8%/month. Annualised volatility = 2.8% × √12 = 9.7%.
How to interpret
Typical annualised volatility ranges for Indian funds:
| Category | Typical σ range |
|---|---|
| Liquid / overnight | < 0.3% |
| Short duration debt | 0.5–2% |
| Corporate bond / banking PSU | 2–5% |
| Balanced advantage / hybrid | 6–12% |
| Large-cap equity | 12–18% |
| Mid-cap equity | 16–24% |
| Small-cap equity | 20–30%+ |
| Sectoral / thematic | 18–35% |
Volatility above 25% in an equity fund warrants examination — it may indicate high factor concentration or illiquid small-cap holdings that reprice in large gaps.
Limitations + caveats
Volatility treats all deviations equally — an upside surprise of +8% is penalised the same as a −8% loss. Investors typically care only about downside variation; see Downside Deviation and Sortino Ratio for downside-only measures. Volatility is also backward-looking and assumes the return distribution is stationary, which is rarely true across market regimes.
Related metrics
- Downside Deviation — standard deviation of only below-target returns; the downside-only counterpart.
- Sharpe Ratio — normalises excess return by volatility; this σ is the denominator.
- Sortino Ratio — uses downside deviation as denominator instead of total volatility.
Sources
Monthly NAV: AdvisorKhoj API. Volatility recomputed monthly using trailing 36-month return series. Minimum 12 months of history required to display; 24 months for reliable σ estimation.