State Street SPDR S&P Biotech ETF Asy. MEM Volatility Analysis
Volatility prediction for Tuesday, July 21st, 2026
1 Day
36.25%
increased by 2.74%
1 Week
36.01%
increased by 2.50%
1 Month
35.18%
increased by 1.67%
Analysis last updated: Monday, July 20, 2026 at 09:52 PM UTC
News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Feb 6, 2006 to Jul 17, 2026Model Insight
This asset exhibits a notable leverage effect: negative returns increase next-day volatility 81% more than equivalent positive returns.
μ
AMEM Model
Tap to view equation
| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0932 | 29.66*** |
α ARCH Response to squared shocks | 0.1339 | 29.44*** |
β GARCH Volatility persistence | 0.7869 | 219.92*** |
γ leverage Additional response to negative shocks | 0.1091 | 14.10*** |
Persistence:
0.975
Half-life:
28 days
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