Pemberian fasilitas pembiayaan transaksi efek dalam rangka transaksi (marjin margin trading) dan penyelesaian sengketa yang timbul di pasar modal : studi kasus : putusan arbitrase antara Ronny Susanto melawan PT Mandiri Sekuritas = Provision of securities transaction financing facility in the framework of margin transaction and the settlement of disputes arised in capital market : case study arbitration award between Ronny Susanto against PT Mandiri Sekuritas