The purpose of this study is to evaluate the relative performance of the portfolio management companies traded on BIST. Using data envelopment analysis, the study covers the period between 2019 and 2022. In the study investigating the impact of the COVID-19 pandemic period on the performance of portfolio management companies, the period of 2019 is considered as pre-COVID-19 pandemic, the years 2020 and 2021 as the COVID-19 pandemic period, and the year 2022 as the post-COVID-19 pandemic period. Within the scope of data envelopment analysis, outout oriented BCC and CCR models based on constant and variable returns to scale were used in the study and efficient firms were identified. According to the results of the CCR model based on constant returns to scale, 31% of the firms in the pre-pandemic period, 24% in the pandemic period and 17% after the pandemic achieved full efficiency. According to the results of the BCC model based on variable returns to scale, 51% of the analyzed firms continued their activities effectively before and during the pandemic, while this rate decreased to 31% in the post-pandemic period. In this context, it has been concluded that the COVID-19 pandemic period had an impact on the relative performance of portfolio management companies.