V-Lab
State Street Health Care Select Sector SPDR ETF AGARCH Volatility Analysis
Volatility prediction for Wednesday, October 7th, 2026
1 Day
14.65%
decreased by 0.39%
1 Week
14.87%
decreased by 0.17%
1 Month
15.56%
increased by 0.52%
Analysis last updated: Tuesday, October 6, 2026 at 09:55 PM UTC
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News Impact Curve
How returns affect tomorrow's volatilityVolatility Forecast
How volatility evolves over timeParameter Estimates
Dec 22, 1998 to Oct 2, 2026Model Insight
The news-impact curve is shifted (γ = 0.64) so that negative returns raise next-day volatility more than positive returns of the same size. The gap is largest for small shocks and narrows for larger ones.
σ
AGARCH Model
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Asymmetry: negative returns raise volatility more
| Param | Value | t-stat |
|---|---|---|
| ωconst | 0.0011 | 0.14 |
| αARCH | 0.0887 | 8.30*** |
| βGARCH | 0.8820 | 77.63*** |
| γleverage | 0.6444 | 7.49*** |
0.971
Persistence23d
Half-lifeσ
AGARCH Model
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| Parameter | Value | t-statistic |
|---|---|---|
ω const Unconditional variance weight | 0.0011 | 0.14 |
α ARCH Response to squared shocks | 0.0887 | 8.30*** |
β GARCH Volatility persistence | 0.8820 | 77.63*** |
γ leverage Additional response to negative shocks | 0.6444 | 7.49*** |
Persistence:
0.971
Half-life:
23 days
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