S&P / ASX 200 Volatility Index APARCH Volatility Analysis
Volatility prediction for Friday, July 17th, 2026
1 Day
81.69%
decreased by 5.49%
1 Week
87.35%
increased by 0.17%
1 Month
99.98%
increased by 12.80%
Analysis last updated: Friday, July 17, 2026 at 11:35 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 2008 to Apr 4, 2025Model Insight
Volatility shocks decay with a half-life of 7 trading days, meaning a shock loses half its impact after approximately 7 days. The volatility power δ = 1.21 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
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.0000 | 5.50*** |
α ARCH Response to squared shocks | 0.1395 | 16.93*** |
β GARCH Volatility persistence | 0.7931 | 70.41*** |
γ leverage Additional response to negative shocks | -0.0795 | -1.52 |
δ power Transformation power | 1.2051 | 15.66*** |
Persistence:
0.907
Half-life:
7 days
Other S&P / ASX 200 Volatility Index Analyses
Other APARCH Analyses on Volatility Indices