This study seeks to examine the norms regarding the civil liability of administrators and managers of investment funds (categorized in the regulatory acts of the Brazilian Securities Commission as essential services providers to the investment fund) for damages caused to the funds investors, as well as the criteria to analyze by the decision maker to determine such liability in concrete cases. For this purpose, the analysis made in this study is segmented in successive investigations regarding (i) the contractual relationship between the funds investors and the essential services providers, with special emphasis on the duties attributed to the latter and in the content of the contractual performance owed by these actors; (ii) the occurrence and characteristics of the contractual breach of the duties attributed to the essential services providers in the context of the norms that discipline the civil liability of these actors for damages caused to the funds investors; and (iii) the criteria to be adopted and the issues to be addressed by the decision maker in order to determine the civil liability of essential services before the funds investors in concrete cases.