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S&P MidCap 400 Index GAS-GARCH Student T Volatility Analysis

Volatility prediction for Friday, July 24th, 2026

1 Day

12.49%

decreased by 0.46%

1 Week

12.69%

decreased by 0.26%

1 Month

13.39%

increased by 0.44%

Analysis last updated: Thursday, July 23, 2026 at 11:01 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P MidCap 400 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 Jul 17, 2026

Model Insight

Volatility shocks decay with a half-life of 52 trading days, meaning a shock loses half its impact after approximately 52 days. Returns follow a Student-t distribution with v = 10.90 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

1.3689
11.01***
α

ARCH

Response to squared shocks

0.0888
36.95***
β

GARCH

Volatility persistence

0.9867
705.26***
ν

DF

Student-t tail thickness

10.9022
4.51***

Persistence:

0.987

Half-life:

52 days