Russell 1000 Growth Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Wednesday, October 21st, 2026
1 Day
17.69%
1 Week
17.80%
1 Month
18.23%
Analysis last updated: Wednesday, October 21, 2026 at 09:03 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
May 12, 2000 to Oct 16, 2026Model Insight
With persistence 0.994, volatility shocks have a half-life of 122 trading days (~0.5 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. Returns follow a Student-t distribution with v = 8.38 degrees of freedom, capturing fatter tails than a normal distribution.
GAS-GARCH-T Model
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| Param | Value | t-stat |
|---|---|---|
| ωlong-run | 2.6520 | 1.09 |
| αscore | 0.0948 | 9.72*** |
| βpersistence | 0.9943 | 187.36*** |
| νDF | 8.3788 | 1.63 |
0.994
Persistence122d
Half-lifeGAS-GARCH-T Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω long-run Long-run variance given a price move | 2.6520 | 1.09 |
α score Weight on the scaled score | 0.0948 | 9.72*** |
β persistence Volatility persistence | 0.9943 | 187.36*** |
ν DF Student-t tail thickness | 8.3788 | 1.63 |
Persistence:
0.994
Half-life:
122 days
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