S&P 500 Equal Weight Index (EWI) GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, November 2nd, 2026
1 Day
12.42%
increased by 0.32%
1 Week
12.55%
increased by 0.45%
1 Month
13.02%
increased by 0.92%
Analysis last updated: Friday, October 30, 2026 at 11:05 PM UTC
Press Delete or Backspace to remove this series.
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Oct 30, 2026Model Insight
Volatility shocks decay with a half-life of 69 trading days, meaning a shock loses half its impact after approximately 69 days. Returns follow a Student-t distribution with v = 8.58 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
Tap to view equation
Shock decay: Shocks decay with a 69-day half-lifev = 8.58 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωlong-run | 1.2540 | 1.88* |
| αscore | 0.0846 | 10.11*** |
| βpersistence | 0.9900 | 169.02*** |
| νDF | 8.5830 | 1.47 |
0.990
Persistence69d
Half-life𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω long-run Long-run variance given a price move | 1.2540 | 1.88* |
α score Weight on the scaled score | 0.0846 | 10.11*** |
β persistence Volatility persistence | 0.9900 | 169.02*** |
ν DF Student-t tail thickness | 8.5830 | 1.47 |
Persistence:
0.990
Half-life:
69 days
Other S&P 500 Equal Weight Index (EWI) Analyses
Other GAS-GARCH Student T Analyses on Equity Indices