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State Street Utilities Select Sector SPDR ETF GAS-GARCH Student T Volatility Analysis

Volatility prediction for Tuesday, July 21st, 2026

1 Day

14.85%

decreased by 0.47%

1 Week

14.97%

decreased by 0.35%

1 Month

15.40%

increased by 0.08%

Analysis last updated: Monday, July 20, 2026 at 09:52 PM UTC

Date Range:

from

to

6M ·

1Y ·

2Y ·

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10Y ·

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graph of State Street Utilities Select Sector SPDR ETF GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Dec 22, 1998 to Jul 17, 2026

Model Insight

Volatility shocks decay with a half-life of 48 trading days, meaning a shock loses half its impact after approximately 48 days. Returns follow a Student-t distribution with v = 10.12 degrees of freedom, capturing fatter tails than a normal distribution.

𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

1.3785
11.45***
α

ARCH

Response to squared shocks

0.0829
32.41***
β

GARCH

Volatility persistence

0.9856
757.57***
ν

DF

Student-t tail thickness

10.1239
4.42***

Persistence:

0.986

Half-life:

48 days