The document summarizes the history and details of the State Bank of India (SBI). It describes how SBI originated from the Bank of Calcutta in 1806 and discusses the merging of other banks to form the Imperial Bank of India in 1921, which was later nationalized to become SBI in 1955. It provides key facts about SBI such as its public ownership, large number of employees and branches globally, and its role as the largest bank in India.