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V-Lab

CBOE S&P 500 Left Tail Volatility Index GJR-GARCH Volatility Analysis

Volatility prediction for Friday, August 21st, 2026

1 Day

179.15%

decreased by 2.95%

1 Week

183.04%

increased by 0.94%

1 Month

196.32%

increased by 14.22%

Analysis last updated: Friday, August 21, 2026 at 11:30 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

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graph of CBOE S&P 500 Left Tail Volatility Index GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 3, 2006 to Aug 14, 2026

Model Insight

Volatility shocks decay with a half-life of 41 trading days, meaning a shock loses half its impact after approximately 41 days.

σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

5.0000
14.88***
α

ARCH

Response to squared shocks

0.0973
12.57***
β

GARCH

Volatility persistence

0.8799
226.07***
γ

leverage

Additional response to negative shocks

0.0118
0.71

Persistence:

0.983

Half-life:

41 days