V-Lab
Tokyo Stock Exchange Tokyo Stock Price Index TOPIX GAS-GARCH Student T Volatility Analysis
Volatility prediction for Monday, September 7th, 2026
1 Day
16.15%
decreased by 0.99%
1 Week
16.35%
decreased by 0.79%
1 Month
17.02%
decreased by 0.12%
Analysis last updated: Saturday, September 5, 2026 at 05:57 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 2, 1990 to Sep 4, 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 = 6.32 degrees of freedom, capturing fatter tails than a normal distribution.
𝑓
GAS-GARCH-T Model
Tap to view equation
Shock decay: Shocks decay with a 32-day half-lifev = 6.32 · fat tails
| Param | Value | t-stat |
|---|---|---|
| ωconst | 1.6472 | 2.92*** |
| αARCH | 0.0826 | 9.61*** |
| βGARCH | 0.9784 | 127.93*** |
| νDF | 6.3220 | 2.03** |
0.978
Persistence32d
Half-life𝑓
GAS-GARCH-T Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 1.6472 | 2.92*** |
α ARCH Response to squared shocks | 0.0826 | 9.61*** |
β GARCH Volatility persistence | 0.9784 | 127.93*** |
ν DF Student-t tail thickness | 6.3220 | 2.03** |
Persistence:
0.978
Half-life:
32 days
Other GAS-GARCH Student T Analyses on Equity Indices