Ibovespa Brasil Sao Paulo Stock Exchange Index APARCH Volatility Analysis
Volatility prediction for Tuesday, July 21st, 2026
1 Day
17.63%
1 Week
17.86%
1 Month
18.72%
Analysis last updated: Monday, July 20, 2026 at 10:02 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Jul 17, 2026Model Insight
With persistence 0.997, volatility shocks have a half-life of 203 trading days (~0.8 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. The volatility power δ = 3.00 sits above 2, so large shocks influence volatility more than quadratically, dominating the response more than in standard GARCH.
Leverage: Negative returns increase volatility 119% more than positive returns
APARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0326 | 8.06*** |
α ARCH Response to squared shocks | 0.0389 | 6.30*** |
β GARCH Volatility persistence | 0.9313 | 640.95*** |
γ leverage Additional response to negative shocks | 0.1298 | 14.64*** |
δ power Transformation power | 3.0000 | 10.97*** |
Persistence:
0.997
Half-life:
203 days
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