Nikkei 225 Spline-GARCH Volatility Analysis
Volatility prediction for Tuesday, July 21st, 2026
1 Day
35.58%
increased by 5.67%
1 Week
35.10%
increased by 5.19%
1 Month
33.46%
increased by 3.55%
Analysis last updated: Friday, July 17, 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 Jul 17, 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
Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.2022 | 9.55*** |
α ARCH Response to squared shocks | 0.1123 | 9.85*** |
β GARCH Volatility persistence | 0.8609 | 71.26*** |
Spline Coefficients
K=1
| γ1 | 0.0007 | 1.34 |
Persistence:
0.973
Half-life:
25 days
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