Vertaile menetelmiä

	TGARCH-malli (Threshold GARCH)	EGARCH-malli (Exponential GARCH)
Tieteenala	Ekonometria	Ekonometria
Menetelmäperhe	Regression model	Regression model
Syntyvuosi	1993-1994	1991
Kehittäjä	Zakoian (1994); Glosten, Jagannathan & Runkle (1993)	Daniel B. Nelson
Tyyppi	Asymmetric volatility model	Volatility / conditional variance model
Alkuperäislähde	Zakoian, J.-M. (1994). Threshold heteroskedastic models. Journal of Economic Dynamics and Control, 18(5), 931-955.	Nelson, D. B. (1991). Conditional heteroskedasticity in asset returns: A new approach. Econometrica, 59(2), 347–370.
Rinnakkaisnimet	Threshold GARCH, TGARCH, GJR-GARCH, asymmetric GARCH	Exponential GARCH, EGARCH, Nelson EGARCH, log-GARCH
Liittyvät	6	6
Tiivistelmä	The Threshold GARCH (TGARCH) model extends the standard GARCH framework by allowing positive and negative return shocks to have asymmetric effects on conditional variance. Negative shocks — bad news — typically amplify volatility more than positive shocks of the same magnitude, a stylised fact known as the leverage effect. TGARCH captures this asymmetry through a threshold indicator that switches on when the previous period's shock was negative.	The Exponential GARCH (EGARCH) model, introduced by Nelson (1991), extends the standard GARCH framework by modelling the logarithm of conditional variance. This ensures variance is always positive without parameter constraints and, crucially, allows negative and positive shocks to have asymmetric effects on volatility — capturing the well-known leverage effect in financial markets.