V-Lab
Tokyo Stock Exchange Tokyo Stock Price Index TOPIX GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, August 17th, 2026
1 Day
17.38%
decreased by 0.71%
1 Week
17.51%
decreased by 0.58%
1 Month
17.98%
decreased by 0.11%
Analysis last updated: Saturday, August 15, 2026 at 05:47 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Aug 14, 2026Model Insight
Volatility shocks decay with a half-life of 32 trading days, meaning a shock loses half its impact after approximately 32 days. Returns follow a Student-t distribution with v = 6.36 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 | 1.6487 | 11.81*** |
α ARCH Response to squared shocks | 0.0830 | 38.61*** |
β GARCH Volatility persistence | 0.9784 | 515.49*** |
ν DF Student-t tail thickness | 6.3605 | 8.12*** |
Persistence:
0.978
Half-life:
32 days
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