This paper presents the first results of our most recent research on the Bilbao Stock Exchange (BSE) from its foundation in 1890 up to the Spanish Civil War. We examine the origin of the Exchange and follow its evolution over the first half-century of existence. To this end we introduce some of the stock exchange indexes we have calculated for Bilbao and put them into comparative perspective with the existing series on general economic and industrial activity and the indexes for other Spanish exchanges for the period considered. These comparisons show Bilbao’s evolution from a public debt-dominated market to an industrial exchange very much tied to regional development. Finally, we contrast the degree of financial market integration associated with the existing Spanish exchange indexes. Our analysis finds strong support for considering the BSE index as an industrial index and little evidence of capital market integration between the principal Spanish exchanges before the 1920s.