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V-Lab

CBOE S&P 500 One-Year Volatility Index Spline-GARCH Volatility Analysis

Volatility prediction for Friday, September 4th, 2026

1 Day

28.30%

decreased by 3.33%

1 Week

28.82%

decreased by 2.81%

1 Month

29.76%

decreased by 1.87%

Analysis last updated: Friday, September 4, 2026 at 11:31 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of CBOE S&P 500 One-Year Volatility Index SGARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 3, 2007 to Aug 28, 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 5 trading days.

τ

Spline-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

1.4339
6.36***
α

ARCH

Response to squared shocks

0.2382
7.43***
β

GARCH

Volatility persistence

0.6339
16.86***
γi Spline Coefficients
K=2
γ10.0136
2.49**
γ2-0.0263
-2.43**

Persistence:

0.872

Half-life:

5 days