State Street SPDR Bloomberg 1-3 Month T-Bill ETF GARCH Volatility Analysis
Volatility prediction for Tuesday, July 21st, 2026
1 Day
0.31%
unchanged at 0.00%
1 Week
0.31%
unchanged at 0.00%
1 Month
0.31%
unchanged at 0.00%
Analysis last updated: Monday, July 20, 2026 at 09:36 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
May 30, 2007 to Jul 17, 2026Model Insight
With persistence 0.995, volatility shocks have a half-life of 129 trading days (~0.5 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
σ
GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0000 | |
α ARCH Response to squared shocks | 0.0205 | 6.12*** |
β GARCH Volatility persistence | 0.9742 | 320.98*** |
Persistence:
0.995
Half-life:
129 days
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