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V-Lab

American Express Co Zero Slope Spline-GARCH Volatility Analysis

Volatility prediction for Wednesday, September 16th, 2026

1 Day

23.47%

decreased by 0.08%

1 Week

24.31%

increased by 0.76%

1 Month

27.05%

increased by 3.50%

Analysis last updated: Tuesday, September 15, 2026 at 09:20 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of American Express Co S0GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Sep 11, 2026

Model Insight

This model fits a time-varying baseline (a spline), so volatility mean-reverts toward a slowly-shifting long-run level rather than a constant. Short-run deviations decay with a half-life of 34 trading days.

τ

Zero Slope Spline-GARCH Model

Tap to view equation

Time-varying baseline: volatility reverts to a slowly-shifting spline trend
ParamValuet-stat
ωconst1.5178
6.79***
αARCH0.0825
10.46***
βGARCH0.8971
101.20***
γi Spline Coefficients
K=6
γ10.0565
3.63***
γ2-0.1027
-4.15***
γ30.0847
4.94***
γ4-0.0603
-3.65***
γ50.0420
2.19**
γ6-0.0318
-2.14**

0.980

Persistence

34d

Half-life
τ

Zero Slope Spline-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

1.5178
6.79***
α

ARCH

Response to squared shocks

0.0825
10.46***
β

GARCH

Volatility persistence

0.8971
101.20***
γi Spline Coefficients
K=6
γ10.0565
3.63***
γ2-0.1027
-4.15***
γ30.0847
4.94***
γ4-0.0603
-3.65***
γ50.0420
2.19**
γ6-0.0318
-2.14**

Persistence:

0.980

Half-life:

34 days