V-Lab
State Street SPDR Portfolio Aggregate Bond ETF EGARCH Volatility Analysis
Volatility prediction for Tuesday, September 8th, 2026
1 Day
3.91%
decreased by 0.29%
1 Week
3.94%
decreased by 0.26%
1 Month
4.06%
decreased by 0.14%
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
Volatility shocks decay with a half-life of 58 trading days, meaning a shock loses half its impact after approximately 58 days.
σ
EGARCH Model
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Shock decay: Shocks decay with a 58-day half-life
| Param | Value | t-stat |
|---|---|---|
| ωconst | -0.0250 | -2.67*** |
| αARCH | 0.1878 | 5.38*** |
| βGARCH | 0.9882 | 267.08*** |
| γleverage | -0.0322 | -1.38 |
0.988
Persistence58d
Half-lifeσ
EGARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | -0.0250 | -2.67*** |
α ARCH Response to squared shocks | 0.1878 | 5.38*** |
β GARCH Volatility persistence | 0.9882 | 267.08*** |
γ leverage Additional response to negative shocks | -0.0322 | -1.38 |
Persistence:
0.988
Half-life:
58 days
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