V-Lab
S&P 500 Scored & Screened Index (ESG) APARCH Volatility Analysis
Volatility prediction for Thursday, August 20th, 2026
1 Day
11.68%
decreased by 0.85%
1 Week
12.14%
decreased by 0.39%
1 Month
13.72%
increased by 1.19%
Analysis last updated: Wednesday, August 19, 2026 at 11:07 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Apr 28, 2005 to Aug 14, 2026Model Insight
This asset exhibits a strong leverage effect: volatility responds almost entirely to negative shocks. The ARCH response to positive shocks is negligible. The volatility power δ = 0.92 sits below 2, so large shocks influence volatility less than quadratically, a more outlier-robust response than standard GARCH.
σ
APARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0365 | 27.00*** |
α ARCH Response to squared shocks | 0.1045 | 19.69*** |
β GARCH Volatility persistence | 0.8907 | 179.54*** |
γ leverage Additional response to negative shocks | 0.9272 | 12.41*** |
δ power Transformation power | 0.9157 | 25.02*** |
Persistence:
0.970
Half-life:
23 days
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