השוואת שיטות

	מודל פורייה TGARCH	מודל TGARCH (Threshold GARCH)
תחום	אקונומטריקה	אקונומטריקה
משפחה	Regression model	Regression model
שנת המקור	1994 / 2012	1993-1994
הוגה השיטה	Zakoian (1994) for TGARCH; Enders and Lee (2012) for Fourier approximation framework	Zakoian (1994); Glosten, Jagannathan & Runkle (1993)
סוג	Volatility model with asymmetric leverage and Fourier smooth breaks	Asymmetric volatility model
מקור מכונן	Zakoian, J.-M. (1994). Threshold heteroskedastic models. Journal of Economic Dynamics and Control, 18(5), 931-955.	Zakoian, J.-M. (1994). Threshold heteroskedastic models. Journal of Economic Dynamics and Control, 18(5), 931-955.
כינויים	Fourier TGARCH, Fourier Threshold GARCH, Fourier GJR-GARCH, smooth structural break TGARCH	Threshold GARCH, TGARCH, GJR-GARCH, asymmetric GARCH
קשורות	5	6
תקציר	The Fourier TGARCH model extends the Threshold GARCH framework by embedding Fourier trigonometric terms in the conditional variance equation to capture smooth, gradual structural breaks in volatility dynamics. It jointly models asymmetric leverage effects — where negative shocks amplify volatility more than positive shocks of the same magnitude — and time-varying intercept shifts caused by unobserved structural change.	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.