The merger of major Islamic banks in Indonesia such as Bank Nasional Indonesia Syariah (BNIS), Bank Rakyat Indonesia Syariah (BRIS) and Bank Syariah Mandiri (BSM) have highlighted the Islamic banking sector around the world. For three years, Indonesia's three largest Islamic banks have merged. The purpose of this study was to measure and test the impact of the implementation of RGEC (Risk Profile, Good Corporate Governance, Earning, and Capital) on earnings growth of those three islamic banks before and after the merger into Bank Syariah Indonesia (PT. BSI Tbk). This research used PT BSI Tbk's year-end data and used panel data regression in testing RGEC factor for growth profit on financial performance of Indonesian Islamic banks from 2019 to 2020. Quantitative analysis methods based on documentation and literature collection was used for this research. In addition, researcher used Eviews 10 to analyse data. The findings of this study indicate that the merger resulted in a significant increase in performance. Thus, ROA has significant influence to PG.