The effects of the UK’s European Union referendum decision has affected the majority of the world and most news surrounding the topic is based on opinions. The motivation for this study is to create quantitative data surrounding the topic from an international investor’s perspective. This is uncommon as event studies usually assess the effect of an event on one stock within an index or industry, this study increases the scale internationally. The purpose of this study is to investigate whether the UK is or was a viable option for international investors and access the changes since the referendum results. Using the standard deviation, average daily returns and correlations of international investors to the UK, portfolio analysis can be used to measure the changes since the decision. Unexpectedly, the UK was a place of greater returns and lower risk since the referendum decision for most international investors even with a dramatic devaluation of the pound against other currencies. There has been continued disinvestment since the referendum decision which would go against traditional economic theory. This study shows the impact of the event on international investors and their portfolios. Further studies are needed to establish the behavioural economic theory behind the disinvestment.