The National Savings Bank (KOP – Kansallis-Osake-Pankki) arranged an architecture competition in the early 1960s to build a modern commercial building to the Turku city centre, next to the central market square. Architect Viljo Revell, known for bold modernist architecture, won the competition and the eight-storey commercial building was built based on his winning entry. The construction was completed in 1964.
The ground floor was planned for commercial use. The other floors were built for the bank office of the National Savings Bank KOP, the name KOP-kolmio (KOP triangle) was given to the building based on the owner, KOP and the triangular shape of the building.
The refurbishment of the building was made in 2008.