V-Lab
S&P 100 Index AGARCH Volatility Analysis
Volatility prediction for Tuesday, September 8th, 2026
1 Day
12.26%
increased by 1.47%
1 Week
12.62%
increased by 1.83%
1 Month
13.76%
increased by 2.97%
Analysis last updated: Friday, September 4, 2026 at 11:30 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Sep 4, 2026Model Insight
The news-impact curve is shifted (γ = 0.58) so that negative returns raise next-day volatility more than positive returns of the same size. The gap is largest for small shocks and narrows for larger ones.
σ
AGARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0000 | 0.00 |
α ARCH Response to squared shocks | 0.1014 | 8.35*** |
β GARCH Volatility persistence | 0.8716 | 69.48*** |
γ leverage Additional response to negative shocks | 0.5824 | 4.30*** |
Persistence:
0.973
Half-life:
25 days
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