V-Lab
State Street SPDR Portfolio Aggregate Bond ETF GARCH Volatility Analysis
Volatility prediction for Wednesday, September 16th, 2026
1 Day
3.94%
decreased by 0.17%
1 Week
3.97%
decreased by 0.14%
1 Month
4.05%
decreased by 0.06%
Analysis last updated: Tuesday, September 15, 2026 at 09:29 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
May 30, 2007 to Sep 11, 2026Model Insight
With persistence 0.992, volatility shocks have a half-life of 90 trading days (~0.4 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
σ
GARCH Model
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High persistence: persistence 0.992, shock half-life ~90 days
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0008 | 3.61*** |
| αARCH | 0.0859 | 7.24*** |
| βGARCH | 0.9064 | 80.02*** |
0.992
Persistence90d
Half-lifeσ
GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0008 | 3.61*** |
α ARCH Response to squared shocks | 0.0859 | 7.24*** |
β GARCH Volatility persistence | 0.9064 | 80.02*** |
Persistence:
0.992
Half-life:
90 days
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