V-Lab
Ibovespa Brasil Sao Paulo Stock Exchange Index Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Tuesday, September 15th, 2026
1 Day
18.48%
decreased by 0.28%
1 Week
18.56%
decreased by 0.20%
1 Month
18.83%
increased by 0.07%
Analysis last updated: Monday, September 14, 2026 at 09:02 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 11, 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 21 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 | 4.5981 | 5.90*** |
| αARCH | 0.0820 | 8.00*** |
| βGARCH | 0.8859 | 75.57*** |
Spline Coefficients
K=4
| γ1 | 0.0350 | 5.35*** |
| γ2 | -0.0372 | -4.17*** |
| γ3 | 0.0019 | 0.38 |
| γ4 | 0.0029 | 0.92 |
0.968
Persistence21d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 4.5981 | 5.90*** |
α ARCH Response to squared shocks | 0.0820 | 8.00*** |
β GARCH Volatility persistence | 0.8859 | 75.57*** |
Spline Coefficients
K=4
| γ1 | 0.0350 | 5.35*** |
| γ2 | -0.0372 | -4.17*** |
| γ3 | 0.0019 | 0.38 |
| γ4 | 0.0029 | 0.92 |
Persistence:
0.968
Half-life:
21 days
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