This work touches upon the interesting spheres of risk classification, measurement and management in financial institutions. Modern banks as well as real economy agents have numerous credit risk measurement models at their disposal. However, agreement about performance of those models is not that unanimous and to some point the models are blamed for breaking out of 2007 financial crisis. In the theoretical part of the work survey of risk measurement practices is provided. Main types of risks, agents face in their day day-to-day activities, are being investigated. Special focus is paid to the credit risk as a unit of exposure and to the models and techniques of its measurement. Practical part of paper contains reconstruction and accuracy estimation of particular credit risk model (Altman Z-score). In it we simulate and compute Altman Z-score for sample of firms from two chosen sectors in United Kingdom. Main goals of the work are to test accuracy of the model by comparing its outputs to real development, and econometric testing of the specifications of the model itself.