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V-Lab

American Express Co Zero Slope Spline-GARCH Volatility Analysis

Volatility prediction for Tuesday, August 25th, 2026

1 Day

26.62%

decreased by 0.77%

1 Week

27.27%

decreased by 0.12%

1 Month

29.43%

increased by 2.04%

Analysis last updated: Monday, August 24, 2026 at 09:38 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 Aug 21, 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 33 trading days.

τ

Zero Slope Spline-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

1.5167
6.81***
α

ARCH

Response to squared shocks

0.0824
10.45***
β

GARCH

Volatility persistence

0.8971
100.98***
γi Spline Coefficients
K=6
γ10.0568
3.65***
γ2-0.1033
-4.17***
γ30.0852
4.96***
γ4-0.0612
-3.67***
γ50.0435
2.24**
γ6-0.0331
-2.21**

Persistence:

0.980

Half-life:

33 days