V-Lab
State Street SPDR Portfolio Aggregate Bond ETF AGARCH Volatility Analysis
Volatility prediction for Tuesday, September 8th, 2026
1 Day
3.67%
decreased by 0.15%
1 Week
3.71%
decreased by 0.11%
1 Month
3.84%
increased by 0.02%
Analysis last updated: Friday, September 4, 2026 at 10:49 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
May 30, 2007 to Sep 4, 2026Model Insight
With persistence 0.992, volatility shocks have a half-life of 84 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
σ
AGARCH Model
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High persistence: persistence 0.992, shock half-life ~84 days
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0008 | 3.55*** |
| αARCH | 0.0865 | 7.15*** |
| βGARCH | 0.9053 | 77.92*** |
| γleverage | 0.0387 | 1.89* |
0.992
Persistence84d
Half-lifeσ
AGARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0008 | 3.55*** |
α ARCH Response to squared shocks | 0.0865 | 7.15*** |
β GARCH Volatility persistence | 0.9053 | 77.92*** |
γ leverage Additional response to negative shocks | 0.0387 | 1.89* |
Persistence:
0.992
Half-life:
84 days
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