S&P GSCI Petroleum Spot Index APARCH Volatility Analysis
Volatility prediction for Monday, October 19th, 2026
1 Day
28.77%
1 Week
28.97%
1 Month
29.72%
Analysis last updated: Friday, October 16, 2026 at 11:52 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Oct 16, 2026Model Insight
With persistence 0.991, volatility shocks have a half-life of 73 trading days (~0.3 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. The volatility power δ = 1.66 sits below 2, so large shocks influence volatility less than quadratically, a more outlier-robust response than standard GARCH.
APARCH Model
Tap to view equation
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0411 | 4.97*** |
| αARCH | 0.0796 | 7.87*** |
| βGARCH | 0.9187 | 97.48*** |
| γleverage | 0.1185 | 1.78* |
| δpower | 1.6566 | 9.75*** |
0.991
Persistence73d
Half-lifeAPARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0411 | 4.97*** |
α ARCH Response to squared shocks | 0.0796 | 7.87*** |
β GARCH Volatility persistence | 0.9187 | 97.48*** |
γ leverage Additional response to negative shocks | 0.1185 | 1.78* |
δ power Transformation power | 1.6566 | 9.75*** |
Persistence:
0.991
Half-life:
73 days
Other S&P GSCI Petroleum Spot Index Analyses
Other APARCH Analyses on Commodities