V-Lab
Korea Stock Exchange KOSPI 200 Index GJR-GARCH Volatility Analysis
Volatility prediction for Friday, September 4th, 2026
1 Day
62.58%
decreased by 2.63%
1 Week
62.45%
decreased by 2.76%
1 Month
61.93%
decreased by 3.28%
Analysis last updated: Friday, September 4, 2026 at 11:27 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 1990 to Aug 27, 2026Model Insight
With persistence 0.997, volatility shocks have a half-life of 218 trading days (~0.9 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
Leverage: Negative returns increase volatility 125% more than positive returns
σ
GJR-GARCH Model
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High persistence: persistence 0.997, shock half-life ~218 daysLeverage: Negative returns increase volatility 125% more than positive returns
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0162 | 4.29*** |
| αARCH | 0.0472 | 5.34*** |
| βGARCH | 0.9201 | 146.87*** |
| γleverage | 0.0589 | 3.37*** |
0.997
Persistence218d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0162 | 4.29*** |
α ARCH Response to squared shocks | 0.0472 | 5.34*** |
β GARCH Volatility persistence | 0.9201 | 146.87*** |
γ leverage Additional response to negative shocks | 0.0589 | 3.37*** |
Persistence:
0.997
Half-life:
218 days
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