V-Lab
American Express Co Asy. MEM Volatility Analysis
Volatility prediction for Thursday, September 24th, 2026
1 Day
29.04%
decreased by 1.63%
1 Week
29.25%
decreased by 1.42%
1 Month
30.04%
decreased by 0.63%
Analysis last updated: Wednesday, September 23, 2026 at 09:34 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 18, 2026Model Insight
With persistence 0.993, volatility shocks have a half-life of 96 trading days (~0.4 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
Leverage: Negative returns increase volatility 71% more than positive returns
μ
AMEM Model
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High persistence: persistence 0.993, shock half-life ~96 daysLeverage: Negative returns increase volatility 71% more than positive returns
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0485 | 7.25*** |
| αARCH | 0.1308 | 12.04*** |
| βGARCH | 0.8158 | 91.61*** |
| γleverage | 0.0925 | 3.93*** |
0.993
Persistence96d
Half-lifeμ
AMEM Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0485 | 7.25*** |
α ARCH Response to squared shocks | 0.1308 | 12.04*** |
β GARCH Volatility persistence | 0.8158 | 91.61*** |
γ leverage Additional response to negative shocks | 0.0925 | 3.93*** |
Persistence:
0.993
Half-life:
96 days
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