V-Lab
iShares 1-3 Year Treasury Bond ETF Zero Slope Spline-GARCH Volatility Analysis
Volatility prediction for Monday, September 21st, 2026
1 Day
1.61%
increased by 0.07%
1 Week
1.60%
increased by 0.06%
1 Month
1.58%
increased by 0.04%
Analysis last updated: Friday, September 18, 2026 at 10:20 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jul 26, 2002 to Sep 18, 2026Model Insight
This model fits a time-varying baseline (a spline), so volatility mean-reverts toward a slowly-shifting long-run level rather than a constant. Short-run deviations decay with a half-life of 26 trading days.
τ
Zero Slope Spline-GARCH Model
Tap to view equation
Time-varying baseline: volatility reverts to a slowly-shifting spline trend
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.9508 | 3.66*** |
| αARCH | 0.0716 | 6.36*** |
| βGARCH | 0.9019 | 61.35*** |
Spline Coefficients
K=10
| γ1 | -0.3709 | -2.20** |
| γ2 | 0.7641 | 3.03*** |
| γ3 | -0.8523 | -4.08*** |
| γ4 | 0.5802 | 2.92*** |
| γ5 | 0.1753 | 1.13 |
| γ6 | -0.5337 | -3.71*** |
| γ7 | 0.1104 | 0.68 |
| γ8 | 0.6749 | 4.29*** |
| γ9 | -1.0600 | -6.81*** |
| γ10 | 0.6523 | 5.49*** |
0.974
Persistence26d
Half-lifeτ
Zero Slope Spline-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.9508 | 3.66*** |
α ARCH Response to squared shocks | 0.0716 | 6.36*** |
β GARCH Volatility persistence | 0.9019 | 61.35*** |
Spline Coefficients
K=10
| γ1 | -0.3709 | -2.20** |
| γ2 | 0.7641 | 3.03*** |
| γ3 | -0.8523 | -4.08*** |
| γ4 | 0.5802 | 2.92*** |
| γ5 | 0.1753 | 1.13 |
| γ6 | -0.5337 | -3.71*** |
| γ7 | 0.1104 | 0.68 |
| γ8 | 0.6749 | 4.29*** |
| γ9 | -1.0600 | -6.81*** |
| γ10 | 0.6523 | 5.49*** |
Persistence:
0.974
Half-life:
26 days
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