Historical Volatility (HV)
Actual past volatility from price moves
What is Historical Volatility (HV)?
Historical Volatility (HV) Historical volatility (HV) is an alternative name for realized volatility — the statistical measure of past price movement, expressed as an annualized standard deviation of returns. The terms "historical volatility" and "realized volatility" are often used interchangeably, though some practitioners distinguish them: HV typically refers to longer-window measures (60-252 days), while RV often refers to shorter recent windows (5-20 days). The calculation is identical to RV: compute log-returns, take the standard deviation, annualize by √252 trading days. The result is the asset's historical price-movement intensity over the specified window, expressed in the same units as implied volatility. Common historical volatility windows: - **30-day HV**: short-term recent volatility - **60-day HV**: two-month rolling baseline - **90-day HV**: quarterly view - **252-day HV** (1-year): annual volatility baseline - **Long-run HV** (5+ years): historical normal for the underlying HV vs IV — the key relationship: Historical volatility is what *actually happened*; implied volatility is what the *market expects to happen*. The relationship between them is the volatility risk premium (VRP): - **VRP > 0** (IV > HV): the market is pricing more volatility than has occurred. Premium-selling has edge. - **VRP < 0** (IV < HV): the market is pricing less volatility than has occurred. Premium-buying has edge. Over multi-year periods, VRP is structurally positive on equity indices (typically 2-5 vol points). This is the foundation of systematic premium-selling profitability. HV-based trading strategies: **HV percentile screens**: filter stocks where current HV is in the bottom quartile of its 1-year range — vol-compression candidates that may be due for expansion (long premium plays). **HV vs IV spread analysis**: rank stocks by IV-HV spread. Largest positive spreads (IV most overpriced vs HV) are premium-selling candidates. **Volatility cone analysis**: plot HV at various windows (10-day, 30-day, 60-day, 90-day) and compare to historical ranges. Identifies which time horizons are expressing unusual volatility. **Pair trading on HV mismatch**: when two correlated stocks have diverging HVs, the lower-HV name may be due for vol expansion or the higher-HV name may be due for compression. For retail options traders, HV's primary use is as a benchmark for IV. Knowing AAPL's 60-day HV is 22% provides context for whether AAPL's current 28% IV is rich, fair, or cheap. Most options platforms display HV alongside IV; the spread between them is among the most useful single signals for premium-selling decisions. HV is also useful for backtesting. When evaluating whether a strategy works, comparing expected returns to realized vol provides realistic Sharpe ratio estimates.
Complete Definition
Historical volatility (HV) is an alternative name for realized volatility — the statistical measure of past price movement, expressed as an annualized standard deviation of returns. The terms "historical volatility" and "realized volatility" are often used interchangeably, though some practitioners distinguish them: HV typically refers to longer-window measures (60-252 days), while RV often refers to shorter recent windows (5-20 days). The calculation is identical to RV: compute log-returns, take the standard deviation, annualize by √252 trading days. The result is the asset's historical price-movement intensity over the specified window, expressed in the same units as implied volatility. Common historical volatility windows: - **30-day HV**: short-term recent volatility - **60-day HV**: two-month rolling baseline - **90-day HV**: quarterly view - **252-day HV** (1-year): annual volatility baseline - **Long-run HV** (5+ years): historical normal for the underlying HV vs IV — the key relationship: Historical volatility is what *actually happened*; implied volatility is what the *market expects to happen*. The relationship between them is the volatility risk premium (VRP): - **VRP > 0** (IV > HV): the market is pricing more volatility than has occurred. Premium-selling has edge. - **VRP < 0** (IV < HV): the market is pricing less volatility than has occurred. Premium-buying has edge. Over multi-year periods, VRP is structurally positive on equity indices (typically 2-5 vol points). This is the foundation of systematic premium-selling profitability. HV-based trading strategies: **HV percentile screens**: filter stocks where current HV is in the bottom quartile of its 1-year range — vol-compression candidates that may be due for expansion (long premium plays). **HV vs IV spread analysis**: rank stocks by IV-HV spread. Largest positive spreads (IV most overpriced vs HV) are premium-selling candidates. **Volatility cone analysis**: plot HV at various windows (10-day, 30-day, 60-day, 90-day) and compare to historical ranges. Identifies which time horizons are expressing unusual volatility. **Pair trading on HV mismatch**: when two correlated stocks have diverging HVs, the lower-HV name may be due for vol expansion or the higher-HV name may be due for compression. For retail options traders, HV's primary use is as a benchmark for IV. Knowing AAPL's 60-day HV is 22% provides context for whether AAPL's current 28% IV is rich, fair, or cheap. Most options platforms display HV alongside IV; the spread between them is among the most useful single signals for premium-selling decisions. HV is also useful for backtesting. When evaluating whether a strategy works, comparing expected returns to realized vol provides realistic Sharpe ratio estimates.
Example
MSFT's 60-day HV is 18%. Current 30-day IV is 24%. IV-HV spread = 6 percentage points — meaningful VRP, suggesting MSFT options are overpriced relative to recent realized movement. A premium-selling iron condor on MSFT has structural edge in this regime.
Related Terms
Frequently Asked Questions
What's the difference between historical volatility and realized volatility?
They're essentially the same — both measure actual past price movement statistically. 'Historical volatility' is often used for longer-window measures (60-252 days); 'realized volatility' for shorter recent windows (5-20 days). Both compute log-return standard deviation × √252 for annualization.
How is historical volatility different from implied volatility?
Historical vol measures what actually happened (past prices). Implied vol prices what the market expects (forward-looking, from options prices). The IV-HV spread is the volatility risk premium — typically positive on equity indices (2-5 vol points), which is the structural edge of premium selling.
How can I use historical volatility for trading?
Compare current IV to recent HV — if IV is meaningfully above HV, premium-selling has edge. Compare different HV windows on the same stock to identify vol-regime shifts. Use HV percentile rankings to find names with compressed vol that may be due for expansion.
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