Joh. Berenberg, Gossler & Co. KG, commonly known as Berenberg Bank and also branded as simply Berenberg, is a Hamburg-based multinational full-service investment bank.

It was founded by the Flemish-origined Berenberg family in 1590 (430 years ago) and is the world's oldest merchant bank. Its owners, the Berenberg/Gossler family, belonged to the ruling elite of Hanseatic merchants of the city-republic of Hamburg and several family members served in the city-state's government from 1735.

Like many other merchant bankers, the Berenbergs were originally cloth merchants.The bank's name refers to Johann Berenberg, his son-in-law Johann Hinrich Gossler and the latter's son-in-law L.E. Seyler, and has remained unchanged since 1791. The bank has operated continuously since 1590 and is still part-owned by members of the Berenberg-Gossler family.

Berenberg Bank is active in investment banking, particularly pan-European equity research, brokerage and capital markets transactions, in addition to private banking for wealthy customers and institutional asset management. Since the 2000s the company has increasingly focused on investment banking.

Berenberg Bank has around 1,600 employees; in addition to its headquarters in Hamburg, it has significant presences in London, Zurich, Frankfurt and New York City, and 11 further offices in Europe, the Americas and Asia. After years of expanding its activities in London, which is now the second largest office and seat of most of its investment banking activities, Berenberg Bank has recently focused on expanding in the United States and Asia.

The bank is organized as a limited partnership with personally liable partners, and is noted for its conservative business strategy. Following the 2000s financial crisis, the bank has expanded rapidly.

The current senior partner and head of the bank Hans-Walter Peters is also President of the Association of German Banks, having succeeded Deutsche Bank CEO Jürgen Fitschen in 2016. In 2018 Berenberg Bank, in line with its increasing focus on investment banking, sold its Swiss private banking subsidiary Berenberg Bank (Schweiz) AG to a group of investors, and the Swiss company will be known as Bergos Berenberg.

According to oldest.org and en.wikipedia