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

Volatility prediction for Wednesday, October 14th, 2026

1 Day

10.15%

decreased by 0.57%

1 Week

10.37%

decreased by 0.35%

1 Month

11.14%

increased by 0.42%

Analysis last updated: Tuesday, October 13, 2026 at 11:01 PM UTC

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Date Range:

from

10/13/2024

to

10/13/2026

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 9, 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 = 6.87 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 = 6.87 · fat tails
ParamValuet-stat
ωconst1.4582
1.31
αARCH0.0855
10.26***
βGARCH0.9916
144.19***
νDF6.8657
2.07**

0.992

Persistence

82d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

1.4582
1.31
α

ARCH

Response to squared shocks

0.0855
10.26***
β

GARCH

Volatility persistence

0.9916
144.19***
ν

DF

Student-t tail thickness

6.8657
2.07**

Persistence:

0.992

Half-life:

82 days