V-Lab
Russell 1000 Growth Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Friday, September 25th, 2026
1 Day
17.09%
1 Week
17.21%
1 Month
17.68%
Analysis last updated: Friday, September 25, 2026 at 08:55 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
May 12, 2000 to Sep 18, 2026Model Insight
With persistence 0.994, volatility shocks have a half-life of 121 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 = 8.40 degrees of freedom, capturing fatter tails than a normal distribution.
GAS-GARCH-T Model
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| Param | Value | t-stat |
|---|---|---|
| ωconst | 2.6309 | 1.10 |
| αARCH | 0.0951 | 9.68*** |
| βGARCH | 0.9943 | 185.85*** |
| νDF | 8.4029 | 1.62 |
0.994
Persistence121d
Half-lifeGAS-GARCH-T Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 2.6309 | 1.10 |
α ARCH Response to squared shocks | 0.0951 | 9.68*** |
β GARCH Volatility persistence | 0.9943 | 185.85*** |
ν DF Student-t tail thickness | 8.4029 | 1.62 |
Persistence:
0.994
Half-life:
121 days
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