The State Bank of India is the largest commercial bank in India. The bank in its present form was incorporated in terms of the provisions of State Bank of India Act, 1955. It took over the banking operations of the erstwhile Imperial Bank of India which was established, by the amalgamation of the three Presidency Banks: Bank of Calcutta (1806), Bank of Bombay (1840) and Bank of Madras (1843) into a single Bank called Imperial Bank of India in 1921. Thus State Bank of India has an impeccable banking heritage that dates back to the early 19th century, i.e. over 200 years.