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V-Lab

S&P 500 Growth Index GJR-GARCH Volatility Analysis

Volatility prediction for Tuesday, September 22nd, 2026

1 Day

12.24%

decreased by 0.05%

1 Week

12.50%

increased by 0.21%

1 Month

13.39%

increased by 1.10%

Analysis last updated: Monday, September 21, 2026 at 11:01 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P 500 Growth Index GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Oct 29, 1992 to Sep 18, 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
ωconst0.0212
5.07***
αARCH0.0070
0.56
βGARCH0.9010
95.46***
γleverage0.1556
7.32***

0.986

Persistence

48d

Half-life
σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0212
5.07***
α

ARCH

Response to squared shocks

0.0070
0.56
β

GARCH

Volatility persistence

0.9010
95.46***
γ

leverage

Additional response to negative shocks

0.1556
7.32***

Persistence:

0.986

Half-life:

48 days