De Beaufort & Kraaijenhage had three partners: the founder Jaap Kraaijenhage, his son Henk, and Jonkheer Johan de Beaufort. De Beaufort was an active member of the Amsterdam Stock Exchange where he had represented the small stockbrokers on the management council since 1962. During the oil crisis, the company went through a difficult period. In 1984, in order to ensure continuity, the two partners Henk Kraaijenhage and Johan de Beaufort took on Kees Swieringa and Jonkheer Reinhard de Beaufort, a distant relation of Johan, as managers. However the new momentum and renewed stock exchange activity could not make up for the simple fact that company was now too small to remain independent.

The search for merger opportunities led the partners to Bank Insinger Willems, which was in a position to bring both scale and a wider range of banking services. Although it was smaller, De Beaufort & Kraaijenhage was more profitable and in the negotiations therefore managed to obtain a 55% share in the capital of the new holding company, founded under the name of Bank Insinger de Beaufort.

Bank Insinger de Beaufort was created on 1 July 1989, moving its offices to Herengracht 504 in 1993.

Bank Insinger de Beaufort at first prospered, but very soon ran into a problem. The balance sheet and assets under management grew fast and soon amounted to 1.6 billion guilders, while at the same time profits had slipped as revenues had come under pressure and administrative expenses had risen hugely. In order to create economies of scale, the bank needed to upsize, and in June 1995 it was finally taken over by Integro, which was closely linked to the South African bank Investec.

In August 2008, BNP Paribas acquired a majority stake in Insinger de Beaufort Holdings B.V., the main shareholder in Bank Insinger de Beaufort N.V.