(14)Due to the fast changing and evolving nature of financial markets, unreliable, inaccurate, incomplete, or outdated data result in errors in the risk estimation and in the calculation of own funds requirements, including in market risk models. In the context of risk management processes of an institution, such erroneous data may also lead to poor management decisions. Consequently, to ensure the reliability and high quality of data and their proper use in the internal processes and the processes for the calculation of own funds requirements, the way data are collected and stored and the procedures for such collecting and storing should be well documented, including a full description of the characteristics, quality checks, automatic filters, and specific sources of daily data. Competent authorities, when they assess market risk internal models, should therefore give particular attention to the quality and reliability of the data used for modelling purposes, and to the processes applied to ensure that such quality and reliability are maintained.