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V-Lab

CBOE S&P 500 6-Month Volatility Index GJR-GARCH Volatility Analysis

Volatility prediction for Friday, August 21st, 2026

1 Day

38.00%

increased by 1.65%

1 Week

40.42%

increased by 4.07%

1 Month

45.73%

increased by 9.38%

Analysis last updated: Friday, August 21, 2026 at 11:32 AM UTC

Date Range:

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to

6M ·

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2Y ·

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graph of CBOE S&P 500 6-Month Volatility Index GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 2008 to Aug 14, 2026

Model Insight

This asset shows a rare inverse leverage effect: volatility responds almost entirely to positive returns, rising far more after gains than after losses. This is the reverse of the usual leverage effect, rare among risky assets.

σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.8751
19.02***
α

ARCH

Response to squared shocks

0.2919
18.95***
β

GARCH

Volatility persistence

0.7725
129.13***
γ

leverage

Additional response to negative shocks

-0.2919
-18.67***

Persistence:

0.918

Half-life:

8 days