This study aims to explore the impact of the Brexit phenomenon on the financial sector, speciallythe issuance of the new regulations in the financial sector by both the UK and the EU. When theUK was a member of the EU, it complied with all financial regulations set by the EU. Variousfinancial regulations were implemented by the EU to maintain the stability and integrity of thefinancial market in the region. One of the consequences of the UK’s exit from the EU (known asBrexit) is changes in regulations, including changes in financial regulations. Post-Brexit, the UKremains one of the world’s largest financial centers and has full freedom to set financial regulationsaccording to national interests. In this context, the EU also anticipates to ensure that UK’s financialpolicies, including post-Brexit financial regulations, does not have a negative impact on the EU’sfinancial market and its member countries. The EU also takes various mitigation measures tomaintain financial market stability throughout the region. This study answers two importantquestions focused on: first, why post-Brexit UK needs to change financial regulations, includingwhat regulations and what their purposes are, and what are the implications of these regulations.Second, why post-Brexit EU needs to change financial regulations, including what regulations andwhat their purposes are, and what are the implications of these regulations. This study uses aqualitative methods and is conducted in multidisciplinary approaches. The theories used in thisstudy are the Financial Resilience Theory by Andrew Haldane and the Hybrid Financial Securityconcept in the context such as financial stability, cybersecurity risks, financial policy regulation,and their relations with national and regional security. The preliminary results of the study indicatethat post-Brexit UK and EU have taken important steps to maintain stability and integrity in thefinancial market both national and European regional interests.

Keywords: United Kingdom, Brexit, European Union, Financial regulation, Financial sectorstability