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V-Lab

Ishares S&P 500 EX S&P 1 ETF Asy. MEM Volatility Analysis

Volatility prediction for Wednesday, September 16th, 2026

1 Day

9.29%

decreased by 0.27%

1 Week

9.33%

decreased by 0.23%

1 Month

9.52%

decreased by 0.04%

Analysis last updated: Tuesday, September 15, 2026 at 09:34 PM UTC

Date Range:

from

to

6M ·

1Y ·

All

graph of Ishares S&P 500 EX S&P 1 ETF AMEM

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jul 9, 2025 to Sep 11, 2026

Model Insight

With persistence 0.999, volatility shocks have a half-life of 785 trading days (~3.1 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.

μ

AMEM Model

Tap to view equation

High persistence: persistence 0.999, shock half-life ~785 days
ParamValuet-stat
ωconst0.0020
0.89
αARCH0.0491
1.20
βGARCH0.9368
34.58***
γleverage0.0264
0.28

0.999

Persistence

785d

Half-life
μ

AMEM Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0020
0.89
α

ARCH

Response to squared shocks

0.0491
1.20
β

GARCH

Volatility persistence

0.9368
34.58***
γ

leverage

Additional response to negative shocks

0.0264
0.28

Persistence:

0.999

Half-life:

785 days