V-Lab
Straits Times Index STI APARCH Volatility Analysis
Volatility prediction for Thursday, August 20th, 2026
1 Day
12.46%
decreased by 0.75%
1 Week
12.76%
decreased by 0.45%
1 Month
13.81%
increased by 0.60%
Analysis last updated: Wednesday, August 19, 2026 at 10:03 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Aug 14, 2026Model Insight
This asset exhibits a strong leverage effect: negative returns increase next-day volatility 140% more than equivalent positive returns. The volatility power δ = 1.60 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 | 0.0261 | 27.86*** |
α ARCH Response to squared shocks | 0.1263 | 41.75*** |
β GARCH Volatility persistence | 0.8662 | 259.33*** |
γ leverage Additional response to negative shocks | 0.2668 | 24.49*** |
δ power Transformation power | 1.6038 | 30.73*** |
Persistence:
0.981
Half-life:
37 days
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