The authors present their arguments and counterarguments on the issue of Immaterial capital and its impact on companies’ performance. The main purpose of the research is to assess companies’ Immaterial Capital and to measure its impact on stock performance. The article has three main objectives: 1) to define immaterial capital and propose a methodology for its assessment; 2) to determine the proportion of Immaterial Capital created in Moroccan companies listed on the Casablanca stock exchange while using the retained measurement methodology; 3) to verify the impact of Immaterial Capital on stock performance. Systematisation literary sources and approaches for solving the problem of Immaterial Capital assessment indicates that there is no broad consensus on that issue. Indeed, given its multidimensional character, immaterial capital is difficult to measure. It is worth to note that several approaches to assessing that capital, which weighs very heavily on the enterprise’s finances, have been developed. In this paper, the authors propose to measure immaterial capital in Moroccan companies listed on the Casablanca Stock exchange, while using two assessing methods, namely price-to-book and Enterprise Value-based approaches. The paper presents the results of an empirical analysis which showed that a lot of sectors create immaterial wealth, in particular telecommunication sector, cement manufacturer, electricity, hydrocarbon distribution, mining, port services, food and beverages, autos distribution and pharmaceutical sector. The research empirically confirmed that all sectors which have a price to book ratio above 3 generate a positive immaterial capital calculated by the second methodology used. The results of the research can be useful for all companies that want to measure their real wealth and consequently to manage their performance competently. It should be noted that the analyses performed in this article are preliminary only. An extension to unlisted companies is intended so that the generalisation of the results would be possible. Keywords assessment, Casablanca stock exchange (CSE), enterprise value (EV), immaterial capital (IC), listed companies, Price-to-Book Ratio (PBR).