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V-Lab

S&P MidCap 400 Index MEM Volatility Analysis

Volatility prediction for Friday, September 11th, 2026

1 Day

10.81%

decreased by 0.25%

1 Week

11.21%

increased by 0.15%

1 Month

12.56%

increased by 1.50%

Analysis last updated: Thursday, September 10, 2026 at 11:01 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P MidCap 400 Index MEM

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jun 3, 1991 to Sep 4, 2026

Model Insight

Volatility shocks decay with a half-life of 47 trading days, meaning a shock loses half its impact after approximately 47 days.

μ

MEM Model

Tap to view equation

Shock decay: Shocks decay with a 47-day half-life
ParamValuet-stat
ωconst0.0245
3.87***
αARCH0.1993
14.99***
βGARCH0.7862
65.47***

0.985

Persistence

47d

Half-life
μ

MEM Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0245
3.87***
α

ARCH

Response to squared shocks

0.1993
14.99***
β

GARCH

Volatility persistence

0.7862
65.47***

Persistence:

0.985

Half-life:

47 days