This study aims to identify the best FINANCIAL RATIOS and the most efficient method for fraud risk detection in the FINANCIAL statements of the listed companies by considering the FINANCIAL importance of decision-making as well as the growing fraud statistics and detrimental effects. The statistical sample included 180 companies listed in the Tehran Stock Exchange from 2014 to 2021 (532 fiscal years suspected of fraud and 908 non-fraudulent fiscal years). Theoretical foundations were first taken into account to extract 96 FINANCIAL RATIOS. The k-NN algorithm, Bayesian network, support vector machine, and bagging method were then employed for fraud risk detection in FINANCIAL statements. According to the findings, the adopted methods failed to meet the evaluation standards in general. With an accuracy of 70. 60% and a proportionality function value of 0. 2940, the gray wolf optimization (GWO) algorithm was then utilized to reduce the RATIOS in order to improve performance. After 31 iterations, nine appropriate FINANCIAL RATIOS were determined. The extracted FINANCIAL RATIOS were then used to reevaluate the effectiveness of the proposed fraud detection strategies. After the FINANCIAL RATIOS were reduced, all of the proposed approaches yielded better results. The accuracy and efficiency of the bagging method, support vector machine, Bayesian network, and k-NN algorithm were reported 79. 25% and 81. 70%, 75. 83% and 80. 30%, 72. 01% and 74. 60%, and 74. 55% % and 75. 60%, respectively. In conclusion, the bagging method outperformed the other approaches in terms of accuracy and efficiency.