American Express Co GJR-GARCH Volatility Analysis
Volatility prediction for Friday, October 23rd, 2026
1 Day
19.03%
decreased by 0.45%
1 Week
19.43%
decreased by 0.05%
1 Month
20.91%
increased by 1.43%
Analysis last updated: Thursday, October 22, 2026 at 09:33 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Oct 16, 2026Model Insight
With persistence 0.997, volatility shocks have a half-life of 201 trading days (~0.8 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
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High persistence: persistence 0.997, shock half-life ~201 daysLeverage: volatility responds almost entirely to negative shocks
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0354 | 4.30*** |
| αARCH | 0.0175 | 3.43*** |
| βGARCH | 0.9277 | 186.51*** |
| γleverage | 0.1027 | 6.61*** |
0.997
Persistence201d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0354 | 4.30*** |
α ARCH Response to squared shocks | 0.0175 | 3.43*** |
β GARCH Volatility persistence | 0.9277 | 186.51*** |
γ leverage Additional response to negative shocks | 0.1027 | 6.61*** |
Persistence:
0.997
Half-life:
201 days
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