V-Lab
American Express Co GJR-GARCH Volatility Analysis
Volatility prediction for Monday, July 27th, 2026
1 Day
36.18%
increased by 8.55%
1 Week
36.31%
increased by 8.68%
1 Month
36.83%
increased by 9.20%
Analysis last updated: Friday, July 24, 2026 at 10:19 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Jul 24, 2026Model Insight
With persistence 0.997, volatility shocks have a half-life of 221 trading days (~0.9 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
Leverage: volatility responds almost entirely to negative shocks
σ
GJR-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0354 | 17.05*** |
α ARCH Response to squared shocks | 0.0170 | 13.27*** |
β GARCH Volatility persistence | 0.9277 | 747.56*** |
γ leverage Additional response to negative shocks | 0.1043 | 26.81*** |
Persistence:
0.997
Half-life:
221 days
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