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V-Lab

CBOE Skew Index Zero Slope Spline-GARCH Volatility Analysis

Volatility prediction for Friday, August 21st, 2026

1 Day

38.28%

decreased by 1.99%

1 Week

44.26%

increased by 3.99%

1 Month

50.96%

increased by 10.69%

Analysis last updated: Friday, August 21, 2026 at 11:31 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of CBOE Skew Index S0GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Aug 14, 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 3 trading days.

τ

Zero Slope Spline-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

2.8476
4.24***
α

ARCH

Response to squared shocks

0.2656
11.00***
β

GARCH

Volatility persistence

0.5272
14.91***
γi Spline Coefficients
K=10
γ10.0950
2.10**
γ2-0.0512
-0.85
γ3-0.0837
-1.96*
γ40.1281
2.87***
γ5-0.2029
-5.25***
γ60.2104
5.67***
γ7-0.1275
-3.80***
γ8-0.0243
-0.76
γ90.1343
4.16***
γ10-0.1125
-4.73***

Persistence:

0.793

Half-life:

3 days