The business world today sometimes faces unexpected challenges, such as the financial crises and the Corona pandemic, which greatly affect the optimal investment. Therefore, due to the uncertainty in the business environment, banks must maintain the necessary liquidity to be able to overcome any financial problem in times of crisis, and the choice of this policy depends largely on liquidity. This study aims to achieve two main goals: First goal is to measure the extent of the influence of moderate policy on optimal investment. Second goal is measure the impact of optimal investment on investors' decisions. To achieve these two goals, this study uses a questionnaire distributed to (13) banks, from which (120) answers were obtained from which the effect of moderate policy in determining the optimal investment was studied. Using the statistical program (Smart-PLS) the questionnaire was analyzed, where the results of this study indicated that the moderate policy affects the optimal investment in a positive way, and thus its reflection on the decisions of investors in a positive way. The two hypotheses of the study were accepted because (P value = 0.000) is the highest degree of acceptance.