V-Lab
AT&T Inc GJR-GARCH Volatility Analysis
Volatility prediction for Monday, September 14th, 2026
1 Day
23.48%
increased by 0.28%
1 Week
23.52%
increased by 0.32%
1 Month
23.67%
increased by 0.47%
Analysis last updated: Saturday, September 12, 2026 at 12:33 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 11, 2026Model Insight
Volatility shocks decay with a half-life of 68 trading days, meaning a shock loses half its impact after approximately 68 days.
σ
GJR-GARCH Model
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Shock decay: Shocks decay with a 68-day half-life
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0262 | 5.07*** |
| αARCH | 0.0413 | 4.97*** |
| βGARCH | 0.9361 | 141.07*** |
| γleverage | 0.0248 | 1.54 |
0.990
Persistence68d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0262 | 5.07*** |
α ARCH Response to squared shocks | 0.0413 | 4.97*** |
β GARCH Volatility persistence | 0.9361 | 141.07*** |
γ leverage Additional response to negative shocks | 0.0248 | 1.54 |
Persistence:
0.990
Half-life:
68 days
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