V-Lab
Nikkei 225 Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Monday, September 28th, 2026
1 Day
19.09%
increased by 0.32%
1 Week
19.31%
increased by 0.54%
1 Month
20.02%
increased by 1.25%
Analysis last updated: Friday, September 25, 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 25, 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 25 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
Time-varying baseline: volatility reverts to a slowly-shifting spline trend
| Param | Value | t-stat |
|---|---|---|
| ωconst | 1.1348 | 10.64*** |
| αARCH | 0.1115 | 9.72*** |
| βGARCH | 0.8612 | 70.89*** |
Spline Coefficients
K=1
| γ1 | 0.0002 | 1.42 |
0.973
Persistence25d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.1348 | 10.64*** |
α ARCH Response to squared shocks | 0.1115 | 9.72*** |
β GARCH Volatility persistence | 0.8612 | 70.89*** |
Spline Coefficients
K=1
| γ1 | 0.0002 | 1.42 |
Persistence:
0.973
Half-life:
25 days
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