V-Lab
Schwab Core Bond ETF GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, September 21st, 2026
1 Day
4.50%
increased by 0.07%
1 Week
4.51%
increased by 0.08%
1 Month
4.56%
increased by 0.13%
Analysis last updated: Friday, September 18, 2026 at 11:09 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Feb 5, 2025 to Sep 18, 2026Model Insight
With persistence 0.995, volatility shocks have a half-life of 142 trading days (~0.6 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. Returns follow a Student-t distribution with v = 159.54 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
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High persistence: persistence 0.995, shock half-life ~142 daysv = 159.54 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.1232 | 2.31** |
| αARCH | 0.0576 | 2.12** |
| βGARCH | 0.9951 | 148.17*** |
| νDF | 159.5379 | 0.01 |
0.995
Persistence142d
Half-life𝑓
GAS-GARCH-T Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.1232 | 2.31** |
α ARCH Response to squared shocks | 0.0576 | 2.12** |
β GARCH Volatility persistence | 0.9951 | 148.17*** |
ν DF Student-t tail thickness | 159.5379 | 0.01 |
Persistence:
0.995
Half-life:
142 days
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