Penggunaan Metode Orthogonal GARCH untuk Meramalkan Matriks Kovarians Return Indeks Harga Saham Sektoral Di Bursa Efek Indonesia
ABSTRACT This study conducted a risk communality assessment on sectoral stock price indices in Indonesia Stock Exchange by using Orthogonal Generalized Autoregressive Conditional Heteroscedasticity (Orthogonal GARCH) method. Data used in this research is daily closing of sectoral stock price indices at Indonesia Stock Exchange which consisting of 10 sectoral price indices. Research period are during January 4, 2011 until July 17, 2017. Of 10 sectoral stock price indices which studied apparently there are two principal component influencing its conditional variance. The result of this research is that stock index of agriculture and mining sector have the same risk factor, while other sectoral stock price indices have the same risk factor. These findings imply that investment managers must differentiate risk factors for agricultural and mining sectors from other sectors. Keywords : Orthogonal GARCH; Indonesia Stock Exchange; Value-at-Risk (VaR); Sectoral stock price indices; Covariance matrix JEL Classification : C58; G11.