Deutsche Bank, Germany’s biggest bank, confirmed recent media speculation by announcing that it was in talks to form a “strategic partnership” with the Luxembourg-headquartered private bank, Sal Oppenheim.

The German banking giant said it has made a “non-binding offer” for a capital stake in Sal Oppenheim. According to a statement, Sal Oppenheim will allow Deutsche Bank to conduct due diligence checks as part of the offer.

The size of any stake, or the financial cost of acquiring it, was not disclosed. However, a spokesperson told WealthBriefing: "Negotiations are going constructively. The aim is a minority stake [in Sal Oppenheim] for now."

“The strategic partnership is intended to give Sal. Oppenheim's customers access to Deutsche Bank's global network and strengthen Deutsche Bank's position in business with affluent private clients in Germany,” Deutsche said in a statement.

One of Europe’s oldest private banks, Sal Oppenheim suffered a net loss of €117 million ($152.5 million) in 2008. The firm has been eyeing the sale of its German BHF banking unit but has reportedly said it is in no hurry to offload this business.

Sal Oppenheim has been a family business since 1789.It employs about 4,000 people and had total assets of €132 billion, according to details on its website.