State Bank of India (SBI) is the largest and oldest bank in India. It is also, measured by the number of branch offices and employees, the largest bank in the world. Established in 1806 as Bank of Bengal, it remains the oldest commercial bank in the Indian Subcontinent

The roots to the State Bank of India are traceable to the first decade of 19th century, when the Bank of Calcutta, later renamed as the Bank of Bengal, was established on 2 June 1806. The Bank of Bengal and two other Presidency banks, namely, the Bank of Bombay (incorporated on 15 April 1840) and the Bank of Madras (incorporated on 1 July 1843) were amalgamated on 27 January 1921, and the reorganized banking entity was named the Imperial Bank of India. All these Presidency banks were incorporated as joint stock companies, and were the result of the royal charters. The Imperial Bank of India continued to remain a joint stock company. Until the establishment of a central bank in India the Imperial Bank and its early predecessors served as the nation’s central bank printing currency.

The Reserve Bank of India, which is the central banking organization of India, in the year 1955, acquired a controlling interest in the Imperial Bank of India and the Imperial Bank of India was christened on 30 April 1955 as the State Bank of India. This acquisition of the controlling interest was done pursuant to the provisions of the State Bank of India Act 1955, an Act enacted by the Parliament of India.