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CBOE S&P 500 Left Tail Volatility Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Friday, August 14th, 2026

1 Day

162.86%

decreased by 13.47%

1 Week

168.99%

decreased by 7.34%

1 Month

188.48%

increased by 12.15%

Analysis last updated: Friday, August 14, 2026 at 11:30 AM UTC

Date Range:

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to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

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

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 3, 2006 to Aug 7, 2026

Model Insight

Volatility shocks decay with a half-life of 29 trading days, meaning a shock loses half its impact after approximately 29 days. Returns follow a Student-t distribution with v = 3.86 degrees of freedom, capturing fatter tails than a normal distribution.

𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

278.5124
5.07***
α

ARCH

Response to squared shocks

0.1058
32.74***
β

GARCH

Volatility persistence

0.9761
217.35***
ν

DF

Student-t tail thickness

3.8577
14.16***

Persistence:

0.976

Half-life:

29 days