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V-Lab

CBOE S&P 500 One-Year Volatility Index Asy. Power MEM Volatility Analysis

Volatility prediction for Monday, August 10th, 2026

1 Day

23.44%

decreased by 5.11%

1 Week

25.89%

decreased by 2.66%

1 Month

33.03%

increased by 4.48%

Analysis last updated: Monday, August 10, 2026 at 11:38 AM UTC

Date Range:

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graph of CBOE S&P 500 One-Year Volatility Index APMEM

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jun 30, 2017 to Aug 7, 2026
Boundary Parameters

Model Insight

This asset shows a rare inverse leverage effect: positive returns raise next-day volatility 14% more than negative returns. Volatility rises more after gains than after losses, the reverse of the usual leverage effect and uncommon among risky assets. The volatility power δ = 0.50 sits below 2, so large shocks influence volatility less than quadratically, a more outlier-robust response than standard GARCH.

μ

APMEM Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.1161
10.94***
α

ARCH

Response to squared shocks

0.3052
20.71***
β

GARCH

Volatility persistence

0.6805
44.95***
γ

leverage

Additional response to negative shocks

-0.1329
-3.80***
δ

power

Transformation power

0.5000
9.43***

Persistence:

0.931

Half-life:

10 days