Business history, if it is to comprehend the men and movements with which it deals, must of necessity invade other academic fields. This article is an attempt to trace the social and economic influences which fashioned the ultimate business activities of German-Jewish investment bankers in the late nineteenth century. Second only to the group of houses of Yankee origin, the group led by Kuhn, Loeb & Co. provides us with an outstanding example of a business elite in operation. Significant from the point of view of business history is the fact that in origins, early activities, and outlook, these family firms displayed remarkable similarities. Once established in New York they became even more tightly knit through marriage and social life. Only when all these factors have been taken into account can we claim to understand the unique role which these businesses played in the development of the American capital market.