The study looked at how efficient and risky European Union banks were during the 2007-2009 financial crisis. They used a method called stochastic frontier analysis to analyze data from 27 EU countries. The results showed that banks in the old EU countries were better at managing costs but not as good at making profits compared to banks in the new EU countries. Well-capitalized banks with lower credit risk and higher liquidity performed better during the crisis. Overall, banks improved their efficiency levels over time, and the gap between old and new EU member states decreased. Maintaining low levels of risk is crucial for banks during financial crises.