V-Lab
Alphabet Inc APARCH Volatility Analysis
Volatility prediction for Friday, September 11th, 2026
1 Day
28.21%
1 Week
28.83%
1 Month
30.99%
Analysis last updated: Thursday, September 10, 2026 at 09:35 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Aug 19, 2004 to Sep 4, 2026Model Insight
Volatility shocks decay with a half-life of 24 trading days, meaning a shock loses half its impact after approximately 24 days. The volatility power δ = 0.50 sits below 2, so large shocks influence volatility less than quadratically, a more outlier-robust response than standard GARCH.
APARCH Model
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| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0451 | 3.10*** |
| αARCH | 0.0821 | 5.13*** |
| βGARCH | 0.9046 | 44.60*** |
| γleverage | 0.1878 | 1.29 |
| δpower | 0.5000 | 2.85*** |
0.972
Persistence24d
Half-lifeAPARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0451 | 3.10*** |
α ARCH Response to squared shocks | 0.0821 | 5.13*** |
β GARCH Volatility persistence | 0.9046 | 44.60*** |
γ leverage Additional response to negative shocks | 0.1878 | 1.29 |
δ power Transformation power | 0.5000 | 2.85*** |
Persistence:
0.972
Half-life:
24 days
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