This study investigates the effect of the organization performance on two psychological biases, mental accounting and aversion to loss, on financial decisions to both investors and managers. To achieve this, two experiments are conducted. The first experiment consists of 40 graduate students as investors, while the second one consists of 40 accountants in a real estate company as managers. The results of the study indicate that the performance of companies impacts both mental accounting and aversion to loss of investors, whereas the performance of companies affects the mental accounting of managers in making their financial decisions but does not affect the aversion to loss.