In 1859, a group of prominent Quebec citizens decided to create the Banque Nationale. The following year, after the legislature allowed it to incorporate, the bank was opened to the public. It continued to do business until 1924, when it merged with Banque d’Hochelaga to become Banque Canadienne Nationale (BCN).
Before the early 1930s, the bank produced its own currency, but political controversy during the Great Depression made it difficult to decide if Canada should have a centralized monetary system. Up until then, individual banks had issued separate currencies, but the depression incited demands for tighter government regulation. In 1935, the central Bank of Canada became the only bank to issue currency, and the BCN phased out its banknotes.
In 1976, BCN established a branch in New York and became the first Canadian bank to do business in the United States. Due to financial hardship in 1979, BCN merged with Provincial Bank of Canada to form the BNC, or Banque Nationale du Canada (National Bank of Canada).
In 1983 the New York branch expanded and opened an office in Seoul. This led to the acquisition of a Citibank branch named Mercantile Bank of Canada two years later. In 1988, a brokerage firm named Lévesque, Beaubien Inc. was acquired by BNC and is now known as National Bank Financial.
In 1993 the assets of the General Trust of Canada were acquired by BNC, and the following year BNC began a US subsidiary named Natbank. Natbank had branches in Pompano Beach, Florida, as well as a representative office in Mexico City.
In 1995, Natbank opened their second branch in Hollywood, Florida, and an office in Havana. The office in Havana was a direct response to new laws allowing foreign bank representative offices in Cuba.
In 1996, the bank bought out Family Trust Corporation as well as the Municipal Savings and Loans Corporation, both located in Ontario. At this time, stakes in Banco Osorno y La Union were sold to Banco Santander, which acquired the bank through merger.
In 2001, BNC bought 17 branches of the Bank of Montreal in Quebec, while in 2008 Altamira and National Bank merged all Altamira operations into the existing NBC branches. All offices in Beirut, Seoul, Shanghai, Mexico City and Taipei were closed around this time.