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Proshares S&P 500 EX-Technology ETF GAS-GARCH Student T Volatility Analysis

Volatility prediction for Wednesday, September 30th, 2026

1 Day

895.80%

decreased by 122.54%

1 Week

893.70%

decreased by 124.64%

1 Month

885.37%

decreased by 132.97%

Analysis last updated: Tuesday, September 29, 2026 at 09:57 PM UTC

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graph of Proshares S&P 500 EX-Technology ETF GAS-GARCH-T

News Impact Curve

How returns affect tomorrow's volatility

Volatility Forecast

How volatility evolves over time

Parameter Estimates

Sep 24, 2015 to Sep 25, 2026

Model Insight

The estimated Student-t degrees of freedom v = 2.00 sit at the infinite-variance boundary (v → 2): the model is attributing extreme moves to heavy tails rather than to volatility, so the volatility scale is unreliable here. See the boundary-parameters flag.

𝑓

GAS-GARCH-T Model

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Unreliable tails: v = 2.00 sits at the infinite-variance boundary
ParamValuet-stat
ωconst16.7735
3.84***
αARCH0.0921
32.93***
βGARCH0.9976
1,563.70***
νDF2.0001

0.998

Persistence

293d

Half-life
𝑓

GAS-GARCH-T Model

Tap to view equation

ParameterValuet-statistic
ω

const

Unconditional variance weight

16.7735
3.84***
α

ARCH

Response to squared shocks

0.0921
32.93***
β

GARCH

Volatility persistence

0.9976
1,563.70***
ν

DF

Student-t tail thickness

2.0001

Persistence:

0.998

Half-life:

293 days