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CBOE S&P 500 9-Day Volatility Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Wednesday, July 15th, 2026

1 Day

237.41%

decreased by 13.05%

1 Week

223.88%

decreased by 26.58%

1 Month

206.74%

decreased by 43.72%

Analysis last updated: Wednesday, July 15, 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 9-Day 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, 2011 to Jul 10, 2026

Model Insight

Volatility shocks decay with a half-life of 3 trading days, meaning a shock loses half its impact after approximately 3 days. Returns follow a Student-t distribution with v = 5.18 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

155.3730
19.18***
α

ARCH

Response to squared shocks

0.1140
10.69***
β

GARCH

Volatility persistence

0.7726
50.65***
ν

DF

Student-t tail thickness

5.1767
3.21***

Persistence:

0.773

Half-life:

3 days