V-Lab
Ishares S&P 500 EX S&P 1 ETF Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Monday, August 17th, 2026
1 Day
13.69%
unchanged at 0.00%
1 Week
13.69%
unchanged at 0.00%
1 Month
13.69%
unchanged at 0.00%
Analysis last updated: Saturday, August 15, 2026 at 02:35 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jul 9, 2025 to Aug 14, 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 35 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.9775 | 4.10*** |
α ARCH Response to squared shocks | 0.0000 | 0.00 |
β GARCH Volatility persistence | 0.9806 | 24.08*** |
Spline Coefficients
K=1
| γ1 | -0.1367 | -0.45 |
Persistence:
0.981
Half-life:
35 days
Other Ishares S&P 500 EX S&P 1 ETF Analyses
Other Zero Slope Spline-GARCH Analyses on ETFs