Analisis pengaruh kepemilikan asing pada Surat Berharga Negara dan Sertifikat Bank Indonesia terhadap pergerakan return nilai tukar rupiah terhadap US dolar dengan metode arch carch (1,1) = Analysis of impact of foreign ownership in Indonesia's Government Security (Surat Berharga Negara) and Bank Indonesia Certificates (Sertificat Bank Indonesia) to return movement of the rupiah against the US dollar utilizing ARCH GARCH (1,1) method