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V-Lab

S&P 500 Equal Weight Index (EWI) GJR-GARCH Volatility Analysis

Volatility prediction for Monday, September 14th, 2026

1 Day

13.33%

decreased by 0.43%

1 Week

13.47%

decreased by 0.29%

1 Month

13.99%

increased by 0.23%

Analysis last updated: Saturday, September 12, 2026 at 12:53 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P 500 Equal Weight Index (EWI) GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 1, 1990 to Sep 11, 2026

Model Insight

This asset exhibits a strong leverage effect: volatility responds almost entirely to negative shocks. The ARCH response to positive shocks is negligible.

σ

GJR-GARCH Model

Tap to view equation

Leverage: volatility responds almost entirely to negative shocks
ParamValuet-stat
ωconst0.0187
5.57***
αARCH0.0173
2.05**
βGARCH0.8985
122.66***
γleverage0.1377
6.78***

0.985

Persistence

45d

Half-life
σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0187
5.57***
α

ARCH

Response to squared shocks

0.0173
2.05**
β

GARCH

Volatility persistence

0.8985
122.66***
γ

leverage

Additional response to negative shocks

0.1377
6.78***

Persistence:

0.985

Half-life:

45 days