“…Since then, multiple extensions of the GARCH scedastic function have been proposed to capture additional stylized facts observed in financial and economic time series, such as nonlinearities, asymmetries, and long-memory properties; see Teräsvirta (2009) for a review. According to the Time Series Analysis (Hyndman 2019) and Empirical Finance (Eddelbuettel 2019) task views at https://CRAN.R-project.org/web/views, the following implementations of univariate GARCH-type models are available in the R (R Core Team 2018) programming language: bayesGARCH (Ardia and Hoogerheide 2010), fGarch (Wuertz, Chalabi, Miklovic, Boudt, and Chausse 2016), GAS (Ardia, Boudt, and Catania 2019b), gets (Pretis, Reade, and Sucarrat 2018), GEVStableGarch (Sousa, Otiniano, Lopes, and Diethelm 2015), lgarch (Sucarrat 2015), rugarch (Ghalanos 2017) and tseries (Trapletti and Hornik 2017). In GARCHtype models, the conditional volatility is driven by shocks in the observed time series.…”