Nationalised Banks are banks, which were acquired by the Government from private firm or person under an Act or Ordinance.
The history of nationalization of Indian banks can be dated back to the year 1955, at the time when the Imperial Bank of India was nationalized. It was then later re-christened as State Bank of India, under the SBI Act, 1955.
In the process of nationalization, the national government or State takes hold over the private industry, organization or assets into public ownership by an Act or ordinance/orders