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V-Lab

Vanguard S&P 500 Index ETF AGARCH Volatility Analysis

Volatility prediction for Monday, August 10th, 2026

1 Day

17.84%

decreased by 1.34%

1 Week

17.53%

decreased by 1.65%

1 Month

16.68%

decreased by 2.50%

Analysis last updated: Saturday, August 8, 2026 at 09:18 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of Vanguard S&P 500 Index ETF AGARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Nov 8, 2012 to Aug 7, 2026

Model Insight

The news-impact curve is shifted (γ = 0.64) so that negative returns raise next-day volatility more than positive returns of the same size. The gap is largest for small shocks and narrows for larger ones.

σ

AGARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0135
4.05***
α

ARCH

Response to squared shocks

0.1036
27.50***
β

GARCH

Volatility persistence

0.8340
157.77***
γ

leverage

Additional response to negative shocks

0.6396
22.82***

Persistence:

0.938

Half-life:

11 days