The worldwide ageing process along with the recent solvency problems of some pension funds have called for an improvement on the regulation of pension plans as well as for the necessity of increasing the control over managers"" behaviour. These features, the growing importance of institutional investing in general and of pension funds in particular and the scarce number of studies focused on pension plans have motivated this work. This thesis, therefore, examines some hot topics related to the performance and management of pensions that deserve great attention of analysis, especially in a growing market such as the Spanish pension industry. This work should help to shed some light on the management of these collective investment portfolios and should be especially useful to both managers and individual investors.