This work focuses on the origins of the Fierro Group. Ildefonso Fierro (1882–1961) was one of the most prominent businessmen of Franco's regime. Fierro's case study presents two features that distinguish it from other Spanish family firms founded in the first half of the twentieth century: its high degree of diversifcation and its peculiar financial history. Prior to the commencement of the Franco dictatorship, Fierro had managed to form a diversifed family business and had bought a bank to finance his industrial activity. This article analyzes how he achieved this and compares his path with that of the Japanese Zaibatsu.