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V-Lab

S&P GSCI Spot Index APARCH Volatility Analysis

Volatility prediction for Monday, October 19th, 2026

1 Day

16.13%

increased by 0.27%

1 Week

16.26%

increased by 0.40%

1 Month

16.75%

increased by 0.89%

Analysis last updated: Friday, October 16, 2026 at 11:52 PM UTC

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Date Range:

from

10/16/2024

to

10/16/2026

6M ·

1Y ·

2Y ·

5Y ·

10Y ·

All

graph of S&P GSCI Spot Index APARCH

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Jan 2, 1990 to Oct 16, 2026

Model Insight

With persistence 0.994, volatility shocks have a half-life of 122 trading days (~0.5 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. The volatility power δ = 1.76 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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High persistence: persistence 0.994, shock half-life ~122 daysδ = 1.76 · sub-quadratic power
ParamValuet-stat
ωconst0.0132
5.28***
αARCH0.0735
8.73***
βGARCH0.9265
114.19***
γleverage0.0305
0.57
δpower1.7579
10.16***

0.994

Persistence

122d

Half-life
σ

APARCH Model

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ParameterValuet-statistic
ω

const

Unconditional variance weight

0.0132
5.28***
α

ARCH

Response to squared shocks

0.0735
8.73***
β

GARCH

Volatility persistence

0.9265
114.19***
γ

leverage

Additional response to negative shocks

0.0305
0.57
δ

power

Transformation power

1.7579
10.16***

Persistence:

0.994

Half-life:

122 days