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V-Lab

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

Volatility prediction for Friday, September 11th, 2026

1 Day

29.10%

increased by 0.85%

1 Week

31.69%

increased by 3.44%

1 Month

36.92%

increased by 8.67%

Analysis last updated: Friday, September 11, 2026 at 11:30 AM UTC

Date Range:

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to

6M ·

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2Y ·

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10Y ·

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

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 3, 2007 to Sep 4, 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

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Inverse leverage: volatility responds almost entirely to positive returns
ParamValuet-stat
ωconst0.6505
7.51***
αARCH0.3594
2.99***
βGARCH0.6987
25.24***
γleverage-0.2997
-2.17**

0.908

Persistence

7d

Half-life
σ

GJR-GARCH Model

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ParameterValuet-statistic
ω

const

Unconditional variance weight

0.6505
7.51***
α

ARCH

Response to squared shocks

0.3594
2.99***
β

GARCH

Volatility persistence

0.6987
25.24***
γ

leverage

Additional response to negative shocks

-0.2997
-2.17**

Persistence:

0.908

Half-life:

7 days