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V-Lab
V-Lab

Ishares S&P 500 EX S&P 1 ETF GJR-GARCH Volatility Analysis

Volatility prediction for Tuesday, September 8th, 2026

1 Day

12.33%

decreased by 0.29%

1 Week

12.44%

decreased by 0.18%

1 Month

12.72%

increased by 0.10%

Analysis last updated: Saturday, September 5, 2026 at 02:27 AM UTC

Date Range:

from

to

6M ·

1Y ·

All

graph of Ishares S&P 500 EX S&P 1 ETF GJR-GARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jul 9, 2025 to Sep 4, 2026

Model Insight

Volatility shocks decay with a half-life of 12 trading days, meaning a shock loses half its impact after approximately 12 days.

σ

GJR-GARCH Model

Tap to view equation

Shock decay: Shocks decay with a 12-day half-life
ParamValuet-stat
ωconst0.0392
0.77
αARCH0.0000
0.00
βGARCH0.8928
7.99***
γleverage0.1021
1.04

0.944

Persistence

12d

Half-life
σ

GJR-GARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0392
0.77
α

ARCH

Response to squared shocks

0.0000
0.00
β

GARCH

Volatility persistence

0.8928
7.99***
γ

leverage

Additional response to negative shocks

0.1021
1.04

Persistence:

0.944

Half-life:

12 days