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V-Lab
V-Lab

IBEX 35 Index Spline-GARCH Volatility Analysis

Volatility prediction for Monday, September 14th, 2026

1 Day

13.25%

increased by 0.32%

1 Week

13.53%

increased by 0.60%

1 Month

14.33%

increased by 1.40%

Analysis last updated: Friday, September 11, 2026 at 04:08 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of IBEX 35 Index SGARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Sep 11, 2026

Model 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 17 trading days.

τ

Spline-GARCH Model

Tap to view equation

Time-varying baseline: volatility reverts to a slowly-shifting spline trend
ParamValuet-stat
ωconst0.8711
5.35***
αARCH0.1106
9.08***
βGARCH0.8488
72.90***
γi Spline Coefficients
K=8
γ1-0.0395
-1.15
γ20.0838
1.42
γ3-0.1123
-2.64***
γ40.1554
5.15***
γ5-0.1605
-6.47***
γ60.0992
3.66***
γ7-0.0264
-0.94
γ8-0.0047
-0.13

0.959

Persistence

17d

Half-life
τ

Spline-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.8711
5.35***
α

ARCH

Response to squared shocks

0.1106
9.08***
β

GARCH

Volatility persistence

0.8488
72.90***
γi Spline Coefficients
K=8
γ1-0.0395
-1.15
γ20.0838
1.42
γ3-0.1123
-2.64***
γ40.1554
5.15***
γ5-0.1605
-6.47***
γ60.0992
3.66***
γ7-0.0264
-0.94
γ8-0.0047
-0.13

Persistence:

0.959

Half-life:

17 days