S&P 500 Index GARCH Volatility Analysis
Volatility prediction for Monday, November 2nd, 2026
1 Day
14.08%
increased by 3.03%
1 Week
14.19%
increased by 3.14%
1 Month
14.57%
increased by 3.52%
Analysis last updated: Saturday, October 31, 2026 at 12:29 AM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Oct 30, 2026Model Insight
Volatility shocks decay with a half-life of 42 trading days, meaning a shock loses half its impact after approximately 42 days.
σ
GARCH Model
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Shock decay: Shocks decay with a 42-day half-life
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0192 | 5.44*** |
| αARCH | 0.1009 | 10.84*** |
| βGARCH | 0.8826 | 97.09*** |
0.984
Persistence42d
Half-lifeσ
GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0192 | 5.44*** |
α ARCH Response to squared shocks | 0.1009 | 10.84*** |
β GARCH Volatility persistence | 0.8826 | 97.09*** |
Persistence:
0.984
Half-life:
42 days
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