V-Lab
CBOE S&P 500 Left Tail Volatility Index GAS-GARCH Student T Volatility Analysis
Volatility prediction for Friday, July 24th, 2026
1 Day
220.72%
increased by 9.44%
1 Week
223.00%
increased by 11.72%
1 Month
230.65%
increased by 19.37%
Analysis last updated: Friday, July 24, 2026 at 11:30 AM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Jan 3, 2006 to Jul 17, 2026Model Insight
Volatility shocks decay with a half-life of 29 trading days, meaning a shock loses half its impact after approximately 29 days. Returns follow a Student-t distribution with v = 3.85 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 | 279.5504 | 5.05*** |
α ARCH Response to squared shocks | 0.1062 | 32.76*** |
β GARCH Volatility persistence | 0.9761 | 216.34*** |
ν DF Student-t tail thickness | 3.8518 | 14.20*** |
Persistence:
0.976
Half-life:
29 days
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