V-Lab
NASDAQ Composite Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Wednesday, September 23rd, 2026
1 Day
18.58%
decreased by 0.74%
1 Week
18.84%
decreased by 0.48%
1 Month
19.63%
increased by 0.31%
Analysis last updated: Wednesday, September 23, 2026 at 12:05 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Sep 18, 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 18 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 | 0.7519 | 7.36*** |
| αARCH | 0.0998 | 10.34*** |
| βGARCH | 0.8632 | 71.99*** |
Spline Coefficients
K=8
| γ1 | 0.0107 | 0.38 |
| γ2 | 0.0448 | 1.02 |
| γ3 | -0.1696 | -5.44*** |
| γ4 | 0.2029 | 7.16*** |
| γ5 | -0.1471 | -5.80*** |
| γ6 | 0.1060 | 3.83*** |
| γ7 | -0.0633 | -2.28** |
| γ8 | 0.0124 | 0.61 |
0.963
Persistence18d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.7519 | 7.36*** |
α ARCH Response to squared shocks | 0.0998 | 10.34*** |
β GARCH Volatility persistence | 0.8632 | 71.99*** |
Spline Coefficients
K=8
| γ1 | 0.0107 | 0.38 |
| γ2 | 0.0448 | 1.02 |
| γ3 | -0.1696 | -5.44*** |
| γ4 | 0.2029 | 7.16*** |
| γ5 | -0.1471 | -5.80*** |
| γ6 | 0.1060 | 3.83*** |
| γ7 | -0.0633 | -2.28** |
| γ8 | 0.0124 | 0.61 |
Persistence:
0.963
Half-life:
18 days
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