Skip to main content
V-Lab
V-Lab

SEI Select Small CAP ETF APARCH Volatility Analysis

Volatility prediction for Wednesday, September 16th, 2026

1 Day

22.05%

increased by 1.18%

1 Week

22.11%

increased by 1.24%

1 Month

22.29%

increased by 1.42%

Analysis last updated: Wednesday, September 16, 2026 at 02:37 AM UTC

Date Range:

from

to

6M ·

1Y ·

All

graph of SEI Select Small CAP ETF APARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Oct 10, 2024 to Sep 11, 2026

Model Insight

Volatility shocks decay with a half-life of 14 trading days, meaning a shock loses half its impact after approximately 14 days. The volatility power δ = 1.23 sits below 2, so large shocks influence volatility less than quadratically, a more outlier-robust response than standard GARCH.

σ

APARCH Model

Tap to view equation

Shock decay: Shocks decay with a 14-day half-lifeδ = 1.23 · sub-quadratic power
ParamValuet-stat
ωconst0.0767
0.77
αARCH0.0522
0.27
βGARCH0.9004
10.79***
γleverage1.0000
0.17
δpower1.2349
1.36

0.951

Persistence

14d

Half-life
σ

APARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0767
0.77
α

ARCH

Response to squared shocks

0.0522
0.27
β

GARCH

Volatility persistence

0.9004
10.79***
γ

leverage

Additional response to negative shocks

1.0000
0.17
δ

power

Transformation power

1.2349
1.36

Persistence:

0.951

Half-life:

14 days