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V-Lab

Howmet Aerospace Inc APARCH Volatility Analysis

Volatility prediction for Wednesday, September 9th, 2026

1 Day

54.59%

increased by 14.28%

1 Week

54.40%

increased by 14.09%

1 Month

53.67%

increased by 13.36%

Analysis last updated: Tuesday, September 8, 2026 at 10:49 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of Howmet Aerospace Inc APARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Sep 4, 2026

Model Insight

With persistence 0.991, volatility shocks have a half-life of 74 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. The volatility power δ = 1.31 sits below 2, so large shocks influence volatility less than quadratically, a more outlier-robust response than standard GARCH.

Leverage: Negative returns increase volatility 226% more than positive returns

σ

APARCH Model

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High persistence: persistence 0.991, shock half-life ~74 daysLeverage: Negative returns increase volatility 226% more than positive returns
ParamValuet-stat
ωconst0.0350
3.91***
αARCH0.0468
6.99***
βGARCH0.9505
158.66***
γleverage0.4214
4.26***
δpower1.3130
7.01***

0.991

Persistence

74d

Half-life
σ

APARCH Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0350
3.91***
α

ARCH

Response to squared shocks

0.0468
6.99***
β

GARCH

Volatility persistence

0.9505
158.66***
γ

leverage

Additional response to negative shocks

0.4214
4.26***
δ

power

Transformation power

1.3130
7.01***

Persistence:

0.991

Half-life:

74 days