S&P SmallCap 600 Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Friday, October 16th, 2026
1 Day
15.93%
increased by 0.93%
1 Week
16.33%
increased by 1.33%
1 Month
17.64%
increased by 2.64%
Analysis last updated: Thursday, October 15, 2026 at 11:02 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Oct 9, 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 29 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 | 0.6372 | 10.21*** |
| αARCH | 0.1004 | 10.88*** |
| βGARCH | 0.8760 | 87.75*** |
Spline Coefficients
K=1
| γ1 | -0.0006 | -4.74*** |
0.976
Persistence29d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.6372 | 10.21*** |
α ARCH Response to squared shocks | 0.1004 | 10.88*** |
β GARCH Volatility persistence | 0.8760 | 87.75*** |
Spline Coefficients
K=1
| γ1 | -0.0006 | -4.74*** |
Persistence:
0.976
Half-life:
29 days
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