The book explores the effects of the Basel II regulations with respect to credit risk on bank performance in terms of Return on Assets and Return on Equity. It includes twelve banks in the period between 2005 and 2012 that use the internal rating-based risk model to calculate the minimum regulatory capital requirements they need to meet. The theoretical framework, built to explore the elements of such interaction between regulations and performance, identifies the financial ratios that could give further insight into the topic.