V-Lab
Nikkei 225 APARCH Volatility Analysis
Volatility prediction for Thursday, September 24th, 2026
1 Day
19.64%
1 Week
19.94%
1 Month
20.89%
Analysis last updated: Friday, September 18, 2026 at 07:03 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 18, 2026Model Insight
This asset exhibits a strong leverage effect: negative returns increase next-day volatility 308% more than equivalent positive returns. The volatility power δ = 1.11 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 | 0.0528 | 7.86*** |
| αARCH | 0.1024 | 9.13*** |
| βGARCH | 0.8828 | 82.05*** |
| γleverage | 0.5585 | 5.61*** |
| δpower | 1.1140 | 8.03*** |
0.967
Persistence21d
Half-lifeAPARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0528 | 7.86*** |
α ARCH Response to squared shocks | 0.1024 | 9.13*** |
β GARCH Volatility persistence | 0.8828 | 82.05*** |
γ leverage Additional response to negative shocks | 0.5585 | 5.61*** |
δ power Transformation power | 1.1140 | 8.03*** |
Persistence:
0.967
Half-life:
21 days
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