The current regulatory framework known as Basel III was adopted in 2010 in response to the major financial crisis triggered by the collapse of investment bank Lehman Brothers in 2008 which resulted in instantaneous and strong turmoil in financial markets, first in the US and then in the rest of the world (especially in the EU). The Basel III framework established stricter capital requirements and introduced a number of measures related to liquidity risk management. Additionally, special requirements were imposed for systemically important banks. Apart from the positive effects of the new regulatory framework (strengthening the capital and liquidity of banks and increasing the ability of the banking sector to overcome market shocks), research examines the impact of the regulatory framework adopted after the major financial crisis on banks' business performance. In order to determine the impact of the post-crisis regulatory framework on banks' activities (in the form of a reduction in total assets, decreased lending activity, including lower levels of profitability and market value of banks), a sample of globally systemically important institutions was defined (30 of them from EU and 26 from the USA) For the institutions concerned, the respective variables (for which previous research were found to adequately reflect regulatory requirements and their impact on the performance indicators of the institutions) were analysed. An emphasis has been put on the existence of differences in the regulatory framework of the two jurisdictions, mainly with the aim of identifying the (non)existence of the impact of the regulatory framework on banks’ performance indicators. Comparing the performance indicators of European and US banks, it is evident that, despite the same starting position (ie the great financial crisis), US banks showed a much faster and stronger level of recovery in all business indicators compared to European banks. Bearing in mind that it is the regulatory framework that determines the activities of banks, based on the results of research, it is clear that the difference in the regulatory response to the financial crisis, which was present between the two jurisdictions (EU and US) ultimately resulted in differences in the business performance of banks in these areas. Thus, it has been proven that regulatory measures in the post-crisis period directly affect the structure of business activities and performance of banks. Therefore, the obtained research results enable a better scientific understanding of the interaction between the macroeconomic environment and the banking sector, especially in the context of further development of an adequate regulatory framework.