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

Volatility prediction for Monday, September 14th, 2026

1 Day

214.53%

increased by 34.70%

1 Week

216.45%

increased by 36.62%

1 Month

221.93%

increased by 42.10%

Analysis last updated: Monday, September 14, 2026 at 03:13 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of CBOE S&P 500 Spot 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 Sep 11, 2026

Model Insight

Volatility shocks decay with a half-life of 13 trading days, meaning a shock loses half its impact after approximately 13 days. Returns follow a Student-t distribution with v = 5.63 degrees of freedom, capturing fatter tails than a normal distribution.

𝑓

GAS-GARCH-T Model

Tap to view equation

Shock decay: Shocks decay with a 13-day half-lifev = 5.63 · fat tails
ParamValuet-stat
ωconst216.6463
2.51**
αARCH0.1197
5.20***
βGARCH0.9491
45.02***
νDF5.6261
1.62

0.949

Persistence

13d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

216.6463
2.51**
α

ARCH

Response to squared shocks

0.1197
5.20***
β

GARCH

Volatility persistence

0.9491
45.02***
ν

DF

Student-t tail thickness

5.6261
1.62

Persistence:

0.949

Half-life:

13 days