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V-Lab

S&P 500 Growth Index GJR-GARCH Volatility Analysis

Volatility prediction for Friday, July 31st, 2026

1 Day

22.03%

decreased by 0.60%

1 Week

21.96%

decreased by 0.67%

1 Month

21.70%

decreased by 0.93%

Analysis last updated: Thursday, July 30, 2026 at 11:06 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

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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 Jul 24, 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

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0210
20.16***
α

ARCH

Response to squared shocks

0.0074
2.36**
β

GARCH

Volatility persistence

0.9013
383.03***
γ

leverage

Additional response to negative shocks

0.1545
28.89***

Persistence:

0.986

Half-life:

49 days