After the financial crisis of 2008, bank profitability became a crucial subject for investors, whose expectations were particularly affected by banks' asset quality and various legal and regulatory issues. In the context of the 2020-2021 COVID-19 pandemic, aspects of bank profitability worsened. For example, data from the European Central Bank indicates euro area banks' ROE fell from 5.3% in 2019 to 1.3% in 2020. We developed a study based on a panel database for 19 European Union countries over the period 2008-2020. The ordinary least squares method using stationarity was employed to determine whether return on equity is influenced by asset quality, operational costs or level of interest. The variables used in our analysis are non-performing loans, loan loss provision ratio and net interest income. Results demonstrate the impact of the variables on banking performance measured through return on equity.