In this study, the goal is to analyze the contagion effect that a bank's failure, Bear Stearns', could have had on two groups of banks in the UK market. The main one is composed of ten banks and the control one of five. The groups of banks were selected based on their assets size. We used an event study and analyzed abnormal returns and cumulative abnormal returns, on different event windows, to study the impact of this announcement on the two samples. After conducting the event study and running both simple and multiple regressions, we found a small contagion effect in the form of negative abnormal returns for three banks following Bear Stearns' failure.