S&P MidCap 400 Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Friday, October 16th, 2026
1 Day
14.03%
increased by 0.58%
1 Week
14.17%
increased by 0.72%
1 Month
14.66%
increased by 1.21%
Analysis last updated: Thursday, October 15, 2026 at 11:01 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Oct 9, 2026Model Insight
Volatility shocks decay with a half-life of 51 trading days, meaning a shock loses half its impact after approximately 51 days. Returns follow a Student-t distribution with v = 10.97 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
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Shock decay: Shocks decay with a 51-day half-lifev = 10.97 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωconst | 1.3595 | 2.79*** |
| αARCH | 0.0884 | 9.28*** |
| βGARCH | 0.9866 | 178.12*** |
| νDF | 10.9710 | 1.12 |
0.987
Persistence51d
Half-life𝑓
GAS-GARCH-T Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.3595 | 2.79*** |
α ARCH Response to squared shocks | 0.0884 | 9.28*** |
β GARCH Volatility persistence | 0.9866 | 178.12*** |
ν DF Student-t tail thickness | 10.9710 | 1.12 |
Persistence:
0.987
Half-life:
51 days
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