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V-Lab

S&P Composite 1500 Index GJR-GARCH Volatility Analysis

Volatility prediction for Monday, September 21st, 2026

1 Day

11.38%

decreased by 0.39%

1 Week

11.69%

decreased by 0.08%

1 Month

12.73%

increased by 0.96%

Analysis last updated: Saturday, September 19, 2026 at 12:01 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P Composite 1500 Index GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Oct 31, 1994 to Sep 18, 2026

Model Insight

Volatility shocks decay with a half-life of 35 trading days, meaning a shock loses half its impact after approximately 35 days.

σ

GJR-GARCH Model

Tap to view equation

Shock decay: Shocks decay with a 35-day half-life
ParamValuet-stat
ωconst0.0246
4.98***
αARCH0.0000
0.00
βGARCH0.8903
97.38***
γleverage0.1804
7.59***

0.980

Persistence

35d

Half-life
σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0246
4.98***
α

ARCH

Response to squared shocks

0.0000
0.00
β

GARCH

Volatility persistence

0.8903
97.38***
γ

leverage

Additional response to negative shocks

0.1804
7.59***

Persistence:

0.980

Half-life:

35 days