This study test and analyze the fundamental factor to Return of Asset (ROA) with Net Interest Margin (NIM) as moderating variable in Book III banks registered in Financial Services Authority (Otoritas Jasa Keuangan (OJK)). The sampling method used was purposive sampling. Of the 110 plantation firms, 24 companies meet the needs of a sample. The method used in this research is multiple linear regression technique and moderate regression technique. The results showed that the Capital Adequacy Ratio (CAR) is significant and has apositive impact on the Net Interest Margin (NIM) and Return Of Assets (ROA). Loan to Deposit Ratio (LDR) and Operating Cost Operating Income (BOPO) is significant and has a negatifimpact on the Net Interest Margin (NIM) and Return Of Assets (ROA). Non-Performing Loans (NPL) is no significant impact on the Net Interest Margin (NIM) of shares and Return Of Assets (ROA). Net Interest Margin (NIM) is capable of moderating the effect of Capital Adequacy Ratio (CAR), Loan to Deposit Ratio (LDR), Operating Cost Operating Income (BOPO), and NonPerforming Loan(NPL) with Capital AdequacyRatio (CAR).

Keywords : Return On Asset (ROA), Net Interest Margin (NIM), Capital Adequacy Ratio (CAR), Loan to Deposit Ratio (LDR), Operating Cost Operating Income(BOPO), And NonPerformingiLoan (NPL).