V-Lab
Apple Inc GJR-GARCH Volatility Analysis
Volatility prediction for Tuesday, September 15th, 2026
1 Day
29.50%
decreased by 0.72%
1 Week
29.81%
decreased by 0.41%
1 Month
30.99%
increased by 0.77%
Analysis last updated: Monday, September 14, 2026 at 09:18 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 11, 2026Model Insight
With persistence 0.998, volatility shocks have a half-life of 367 trading days (~1.5 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
Leverage: Negative returns increase volatility 180% more than positive returns
σ
GJR-GARCH Model
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High persistence: persistence 0.998, shock half-life ~367 daysLeverage: Negative returns increase volatility 180% more than positive returns
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0429 | 3.62*** |
| αARCH | 0.0303 | 4.01*** |
| βGARCH | 0.9406 | 155.88*** |
| γleverage | 0.0545 | 3.37*** |
0.998
Persistence367d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0429 | 3.62*** |
α ARCH Response to squared shocks | 0.0303 | 4.01*** |
β GARCH Volatility persistence | 0.9406 | 155.88*** |
γ leverage Additional response to negative shocks | 0.0545 | 3.37*** |
Persistence:
0.998
Half-life:
367 days
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