What kind of continuities and historical transformations are there between the commercial elite of the colonial period, the coastal plutocracy that flourished in the nineteenth century thanks to the guano trade, and the new economic elite that appeared in the early twentieth century and became consolidated in the following decades? Which were the main economic sectors where the elite invested its wealth? Who were the representatives of the new Peruvian upper class in the early twentieth century? What economic transformations did this class endure throughout the century? How significant was the presence of foreigners in the economic elite? Finally, what was the size of the most important fortunes in the twentieth century? After a brief discussion on sources and methodology, in order to answer these questions the paper has been organized as follows. First a brief summary is presented of the major characteristics of Peru's upper class, and the successive changes the identity of its members underwent. Second, the social composition of the elite that managed to consolidate its economic pre-eminence at the turn of the twentieth century will be examined. Third, the structure of the wealth of this elite will be reconstructed through a quantification of its investments and the composition of its most significant assets. Finally, the various strata that formed this social group will be established in terms of the magnitude of the estate that was accumulated.