Hecq, Alain W. J.; Velasquez-Gaviria, Daniel - In: Econometrics : open access journal 13 (2025) 2, pp. 1-25
Financial assets often exhibit explosive price surges followed by abrupt collapses, alongside persistent volatility … explains time-varying volatility. We propose two estimation approaches: (i) Whittle-based frequency-domain methods, which are … reveal that overlooking noncausality biases GARCH parameters, downplaying short-run volatility reactions to news (𝛼) while …