V-Lab
S&P 500 Index GJR-GARCH Volatility Analysis
Volatility prediction for Monday, August 31st, 2026
1 Day
10.37%
decreased by 0.16%
1 Week
10.68%
increased by 0.15%
1 Month
11.72%
increased by 1.19%
Analysis last updated: Saturday, August 29, 2026 at 12:24 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Aug 28, 2026Model Insight
This asset exhibits a strong leverage effect: volatility responds almost entirely to negative shocks. The ARCH response to positive shocks is negligible.
σ
GJR-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0216 | 5.15*** |
α ARCH Response to squared shocks | 0.0035 | 0.36 |
β GARCH Volatility persistence | 0.8972 | 104.18*** |
γ leverage Additional response to negative shocks | 0.1602 | 7.42*** |
Persistence:
0.981
Half-life:
36 days
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