V-Lab
Merck & Co Inc APARCH Volatility Analysis
Volatility prediction for Wednesday, September 9th, 2026
1 Day
28.12%
1 Week
28.23%
1 Month
28.61%
Analysis last updated: Tuesday, September 8, 2026 at 10:51 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 4, 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 = 0.86 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 | 0.0265 | 3.87*** |
| αARCH | 0.0405 | 5.16*** |
| βGARCH | 0.9545 | 106.17*** |
| γleverage | 0.7503 | 3.63*** |
| δpower | 0.8573 | 4.34*** |
0.985
Persistence47d
Half-lifeAPARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0265 | 3.87*** |
α ARCH Response to squared shocks | 0.0405 | 5.16*** |
β GARCH Volatility persistence | 0.9545 | 106.17*** |
γ leverage Additional response to negative shocks | 0.7503 | 3.63*** |
δ power Transformation power | 0.8573 | 4.34*** |
Persistence:
0.985
Half-life:
47 days
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