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S&P 100 Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Tuesday, November 3rd, 2026

1 Day

15.40%

decreased by 0.05%

1 Week

15.47%

increased by 0.02%

1 Month

15.74%

increased by 0.29%

Analysis last updated: Tuesday, November 3, 2026 at 12:01 AM UTC

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Date Range:

from

11/02/2024

to

11/02/2026

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P 100 Index GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 1, 1990 to Oct 30, 2026

Model Insight

With persistence 0.992, volatility shocks have a half-life of 82 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. Returns follow a Student-t distribution with v = 6.91 degrees of freedom, capturing fatter tails than a normal distribution.

𝑓

GAS-GARCH-T Model

Tap to view equation

High persistence: persistence 0.992, shock half-life ~82 daysv = 6.91 · fat tails
ParamValuet-stat
ωlong-run1.4630
1.31
αscore0.0856
10.24***
βpersistence0.9916
144.67***
νDF6.9055
2.05**

0.992

Persistence

82d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

long-run

Long-run variance given a price move

1.4630
1.31
α

score

Weight on the scaled score

0.0856
10.24***
β

persistence

Volatility persistence

0.9916
144.67***
ν

DF

Student-t tail thickness

6.9055
2.05**

Persistence:

0.992

Half-life:

82 days