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V-Lab

S&P 500 Growth Index AGARCH Volatility Analysis

Volatility prediction for Friday, July 31st, 2026

1 Day

22.42%

increased by 0.29%

1 Week

22.33%

increased by 0.20%

1 Month

22.02%

decreased by 0.11%

Analysis last updated: Thursday, July 30, 2026 at 11:06 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P 500 Growth Index AGARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Oct 29, 1992 to Jul 24, 2026

Model Insight

The news-impact curve is shifted (γ = 0.57) 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

0.0000
0.00
α

ARCH

Response to squared shocks

0.0999
34.19***
β

GARCH

Volatility persistence

0.8799
301.76***
γ

leverage

Additional response to negative shocks

0.5670
17.28***

Persistence:

0.980

Half-life:

34 days