V-Lab
Hong Kong Hang Seng Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, July 27th, 2026
1 Day
22.43%
decreased by 0.27%
1 Week
22.45%
decreased by 0.25%
1 Month
22.51%
decreased by 0.19%
Analysis last updated: Friday, July 24, 2026 at 09:11 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 1, 1990 to Jul 24, 2026Model Insight
With persistence 0.992, volatility shocks have a half-life of 91 trading days (~0.4 years), close to a unit root, so long-run forecasts are highly sensitive to this estimate. Returns follow a Student-t distribution with v = 7.06 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 2.1881 | 6.06*** |
α ARCH Response to squared shocks | 0.0557 | 39.35*** |
β GARCH Volatility persistence | 0.9924 | 741.16*** |
ν DF Student-t tail thickness | 7.0571 | 5.92*** |
Persistence:
0.992
Half-life:
91 days
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