V-Lab
Nikkei Stock Average Volatility Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, August 21st, 2026
1 Day
162.81%
decreased by 19.38%
1 Week
156.83%
decreased by 25.36%
1 Month
148.43%
decreased by 33.76%
Analysis last updated: Friday, August 21, 2026 at 08:17 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 1990 to Jul 31, 2026Model Insight
This model fits a time-varying baseline (a spline), so volatility mean-reverts toward a slowly-shifting long-run level rather than a constant. Short-run deviations decay with a half-life of 3 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 2.2759 | 4.68*** |
α ARCH Response to squared shocks | 0.1888 | 7.65*** |
β GARCH Volatility persistence | 0.6125 | 16.83*** |
Spline Coefficients
K=10
| γ1 | 0.1532 | 2.80*** |
| γ2 | -0.1646 | -2.18** |
| γ3 | 0.0093 | 0.20 |
| γ4 | 0.0177 | 0.43 |
| γ5 | -0.0054 | -0.14 |
| γ6 | -0.0484 | -1.06 |
| γ7 | 0.0705 | 1.14 |
| γ8 | -0.0589 | -0.92 |
| γ9 | 0.0641 | 1.29 |
| γ10 | -0.0629 | -1.82* |
Persistence:
0.801
Half-life:
3 days
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