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

Volatility prediction for Friday, July 24th, 2026

1 Day

220.72%

increased by 9.44%

1 Week

223.00%

increased by 11.72%

1 Month

230.65%

increased by 19.37%

Analysis last updated: Friday, July 24, 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 Jul 17, 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 = 3.85 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

279.5504
5.05***
α

ARCH

Response to squared shocks

0.1062
32.76***
β

GARCH

Volatility persistence

0.9761
216.34***
ν

DF

Student-t tail thickness

3.8518
14.20***

Persistence:

0.976

Half-life:

29 days