Société Belge de Banque established the Comptoir Diamantaire Anversois in 1934, in partnership with Banque Transatlantique, Société Internationale Forestière et Minière du Congo (Forminière ), and the De Beers Group. The company was the first financial institution to focus solely and entirely on the needs of the diamond industry; it opened its registered office in the very heart of Antwerp's diamond district.
In 1937, Belgium passed bank reform legislation that allowed the Comptoir Diamantaire Anversois to become a bank. At this point the Comptoir changed its name to Antwerp Diamond Bank (ADB) . It also took the opportunity to double its equity base to BEF60 million (approximately 1.5 million euros) by bringing in Kredietbank and Compagnie Financière et Industrielle (Confindus)-Banque de Bruxelles as shareholders. In 1999, KBC Bank acquired the shares in ADB that Generale Bank (which had merged with Société Belge de Banque in 1965), and Banque Bruxelles Lambert (the result of the 1975 merger of Banque de Bruxelles and Banque Lambert) had held. KBC thereby became the primary shareholder in ADB, increasing its ownership from 37% to 87%. That same year ADB opened a representative office in New York under the name Antwerpse Diamantbank. The next year ADB opened a representative office in Hong Kong. The name of ADB's Swiss subsidiary became Diamond Bank (Switzerland). On 6 December 2001 the New York representative office changed its name to Antwerp Diamond Bank. In 2002, KBC Bank increased its stake in ADB to 99.9%. To do so, KBC bought Henfin Holding, which had represented De Beers on the board of ADB as one of its founding shareholders. That same year ADB opened a branch in Mumbai, the center for India’s diamond industry. This branch has a staff of about 20 persons. (The industry in Mumbai started out with small diamonds, "cutting the uncuttable". It now has a share of the market for moderately big diamonds, once dominated by Tel Aviv, and is starting to encroach on cutting big diamonds, Antwerp's forte.) In 2005, Diamond Bank (Switzerland) opened a representative office in Dubai, UAE. In 2008, ADB established a subsidiary in Singapore: Antwerp Diamond Bank Asia Pacific. This is a regional headquarters that supports and develop activities in Mumbai, Hong Kong and possible future initiatives in China. ADB was the first bank to create a commercial paper program for the diamond industry. The client was an Indian-owned company in Antwerp. In 2008, Diamond Bank (Switzerland) ceased to operate as a subsidiary and instead became a representative office of ADP, which also took over the responsibility for the Dubai rep office. In 2009, ADB signed a memorandum of understanding with the Bank of China.
Presently, specializes exclusively in serving the diamond and the diamond jewelry sector. It is the second largest diamond bank in the world, after ABN AMRO's International Diamond and Jewelry Group. In addition to its headquarters in Antwerp, it has offices covering all the major traditional as well as emerging diamond centers such as Antwerp, Dubai, Geneva, Hong Kong, Mumbai and New York. The ADB group employs approximately 160 people worldwide, of whom about 110 work at the head office in Antwerp. ADB is currently a wholly owned subsidiary of KBC Bank, however, European Competition Commission directed KBC to divest the bank as part of the terms of the Belgian government's bail-out of KBC. KBC agreed in December 2013 to sell ADB to the Chinese Yinren Group. However, the sale requires regulatory approval and is stalled. The sale has failed and KBC stated in September 2014 that it would wind down ADB as no other entity has expressed an interest in buying ADB. ADB would make no new loans and would close out existing loans as they were paid off.