Christiania Bank og Kreditkasse, branded domestically as Kreditkassen or K-Bank and internationally as Christiania Bank was a Norwegian bank that existed between 1848 and 2000 when it merged with MeritaNordbanken and became Nordea. The bank had its headquarters in Oslo and was Norway's second largest bank at the time of the merger.
The bank was founded in Oslo (then called Christiania) in 1848 as Christiania Kreditkasse, though changed its name to Christiania Bank og Kreditkasse in 1862. In 1858, the bank moved out of its temporary location at the home of the bank manager, Fritz Henrich Frölich, and to permanent locations. It opened branches in 1897, under the directorship of Peter Harboe Castberg
The bank expanded out of Oslo in 1957 when it bought Elverum Kreditbank and Hamar Privatbank, and in 1959 with the acquisition of Agder Bank. By 1965, the bank had 18 offices outside Oslo. In 1973, the bank opened its first international office, in Luxembourg. In the 1980s, the bank further acquired Andresens Bank (in 1980), Vestfoldbanken (in 1981) and Fiskernes Bank (in 1983).
In the last years of the 1980s, there was a major financial crisis in Norway and by 1991 the bank had used up all capital. To save the bank, the Government of Norway took over the bank and gave it new capital, rescuing it from bankruptcy. In the early years of the 1990s, the bank also bought Sunnmørsbanken and Sørlandsbanken. In 1995, the government reduced its ownership to 51%, listing it on the Oslo Stock Exchange, and in 1999 to 35%. The same year, the Swedish MeritaNordbanken bid for the bank, and in 2000 the government sold its shares and the bank became part of Nordea. Christiania Bank was at the time of the merger with Nordea Norway's oldest existing bank.