Mulyaningtyas ED, Rokhim R. Evaluation of individual stock portfolio performance on the Indonesia stock exchange using the Ortiz, Jorion, and Markowitz approaches. EMAGRAP [Internet]. 2026 Jul. 28 [cited 2026 Jul. 28];4(1). Available from: https://journal-iasssf.com/index.php/EMAGRAP/article/view/3789