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V-Lab

S&P 1000 Index APARCH Volatility Analysis

Volatility prediction for Monday, September 14th, 2026

1 Day

17.60%

decreased by 0.96%

1 Week

17.74%

decreased by 0.82%

1 Month

18.24%

decreased by 0.32%

Analysis last updated: Saturday, September 12, 2026 at 12:53 AM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P 1000 Index APARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Dec 29, 1994 to Sep 11, 2026

Model Insight

This asset exhibits a strong leverage effect: volatility responds almost entirely to negative shocks. The ARCH response to positive shocks is negligible. The volatility power δ = 1.00 sits below 2, so large shocks influence volatility less than quadratically, a more outlier-robust response than standard GARCH.

σ

APARCH Model

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Leverage: volatility responds almost entirely to negative shocksδ = 1.00 · sub-quadratic power
ParamValuet-stat
ωconst0.0284
8.90***
αARCH0.0783
10.00***
βGARCH0.9162
117.81***
γleverage0.8408
8.97***
δpower0.9975
10.30***

0.979

Persistence

32d

Half-life
σ

APARCH Model

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ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0284
8.90***
α

ARCH

Response to squared shocks

0.0783
10.00***
β

GARCH

Volatility persistence

0.9162
117.81***
γ

leverage

Additional response to negative shocks

0.8408
8.97***
δ

power

Transformation power

0.9975
10.30***

Persistence:

0.979

Half-life:

32 days