CORONA is a comprehensive Performance Attribution and Analysis system for portfolios. It provides tools to analyze the performance of the portfolio and also compare its performance with any peer portfolio or benchmark. It allows the returns of the portfolio to be decomposed along multiple dimensions based on any user-defined criteria and then analyze the returns in terms of its sources. It allows the performance of the portfolio manager to be analyzed in terms of skill. It enables the performance of the portfolio to be analyzed in terms of allocation of assets along multiple dimensions and the returns generated along those dimensions, so that an assessment can be made as to how the different bets taken have performed. It enables comparison of portfolio performance with peer-group portfolios and benchmark indices.