Geneva is host to the most ancient and venerable private banks of Switzerland, but not much is known about the circumstances in which the city allegedly developed an early competitive advantage in wealth management. Using an extraordinary qualitative source (Jacques Mirabaud's papers, and especially his memoirs), this article outlines the microstructure of Genevan private banking at the time of its emergence in the early nineteenth century. It finds that in those years, wealth managers’ ‘raw material’ did not consist of foreign capital, but of a remarkably abundant stock of domestic capital. Financial and social factors were intertwined in producing a very hierarchical division of labour in the origination and distribution of international sovereign loans.