V-Lab
State Street SPDR Portfolio S&P 500 Value ETF GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, August 24th, 2026
1 Day
11.09%
decreased by 0.19%
1 Week
11.31%
increased by 0.03%
1 Month
12.06%
increased by 0.78%
Analysis last updated: Friday, August 21, 2026 at 10:49 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Oct 2, 2000 to Aug 21, 2026Model Insight
Volatility shocks decay with a half-life of 47 trading days, meaning a shock loses half its impact after approximately 47 days. Returns follow a Student-t distribution with v = 6.84 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.1470 | 8.96*** |
α ARCH Response to squared shocks | 0.0950 | 40.70*** |
β GARCH Volatility persistence | 0.9852 | 567.52*** |
ν DF Student-t tail thickness | 6.8430 | 8.49*** |
Persistence:
0.985
Half-life:
47 days
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