Vol. 1 No. 2, 2020 IJEBA International Journal of Economic and Business Applied http://ijeba.makarioz.org/ 93 | Page SINGLE INDEX MODEL APPLICATION IN CALCULATION OF RETURN AND SHARE RISK FORMING OPTIMAL PORTFOLIO IN LQ45 SHARES IN 2019 Novi Puji Lestari 1 , 2 Widhiyo Sudiyono 1,2 Universitas Muhammadiyah Malang, Indonesia 1 novipujilestari61@gmail.com, 2 widhiyosudiyono@gmail.com Abstract This study aims to determine the existence of the calculation of return and risk of companies forming the optimal portfolio based on each company that will be grouped into the business sector. The research results can be used as a reference for potential investors to choose or invest in stocks which are the optimal type of portfolio. This type of research is a quantitative study with purposive sampling technique. The population of this research is companies that are members of the LQ 45 Index with a total of 45 companies. The analysis model used is the Single Index Model. The research period is companies indexed by LQ 45 during 2019, namely 2 periods Key words : Portfolio, Indeks LQ 45, Single Indeks Model