V-Lab
Korea Stock Exchange KOSPI 200 Index GJR-GARCH Volatility Analysis
Volatility prediction for Friday, September 18th, 2026
1 Day
47.85%
decreased by 2.00%
1 Week
47.77%
decreased by 2.08%
1 Month
47.48%
decreased by 2.37%
Analysis last updated: Friday, September 18, 2026 at 09:53 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 1990 to Sep 10, 2026Model Insight
With persistence 0.997, volatility shocks have a half-life of 204 trading days (~0.8 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate.
Leverage: Negative returns increase volatility 124% more than positive returns
σ
GJR-GARCH Model
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High persistence: persistence 0.997, shock half-life ~204 daysLeverage: Negative returns increase volatility 124% more than positive returns
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0166 | 4.36*** |
| αARCH | 0.0477 | 5.36*** |
| βGARCH | 0.9192 | 146.00*** |
| γleverage | 0.0593 | 3.37*** |
0.997
Persistence204d
Half-lifeσ
GJR-GARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0166 | 4.36*** |
α ARCH Response to squared shocks | 0.0477 | 5.36*** |
β GARCH Volatility persistence | 0.9192 | 146.00*** |
γ leverage Additional response to negative shocks | 0.0593 | 3.37*** |
Persistence:
0.997
Half-life:
204 days
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