V-Lab
State Street SPDR S&P Biotech ETF GJR-GARCH Volatility Analysis
Volatility prediction for Tuesday, August 25th, 2026
1 Day
30.62%
decreased by 0.63%
1 Week
30.63%
decreased by 0.62%
1 Month
30.68%
decreased by 0.57%
Analysis last updated: Monday, August 24, 2026 at 09:48 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Feb 6, 2006 to Aug 21, 2026Model Insight
This asset exhibits a strong leverage effect: volatility responds almost entirely to negative shocks. The ARCH response to positive shocks is negligible.
σ
GJR-GARCH Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0764 | 15.79*** |
α ARCH Response to squared shocks | 0.0163 | 7.34*** |
β GARCH Volatility persistence | 0.9136 | 357.30*** |
γ leverage Additional response to negative shocks | 0.1000 | 15.86*** |
Persistence:
0.980
Half-life:
34 days
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