V-Lab
S&P 100 Index GARCH Volatility Analysis
Volatility prediction for Thursday, September 17th, 2026
1 Day
10.76%
decreased by 0.22%
1 Week
11.03%
increased by 0.05%
1 Month
11.96%
increased by 0.98%
Analysis last updated: Thursday, September 17, 2026 at 03:45 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Sep 11, 2026Model Insight
Volatility shocks decay with a half-life of 45 trading days, meaning a shock loses half its impact after approximately 45 days.
σ
GARCH Model
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Shock decay: Shocks decay with a 45-day half-life
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0190 | 5.25*** |
| αARCH | 0.0997 | 10.86*** |
| βGARCH | 0.8849 | 98.16*** |
0.985
Persistence45d
Half-lifeσ
GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0190 | 5.25*** |
α ARCH Response to squared shocks | 0.0997 | 10.86*** |
β GARCH Volatility persistence | 0.8849 | 98.16*** |
Persistence:
0.985
Half-life:
45 days
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