The bank traces its ancestry to British India, through the Imperial Bank of India, to the founding, in 1806, of the Bank of Calcutta, making it the oldest commercial bank in the Indian subcontinent. Bank of Madras merged into the other two "presidency banks" in British India, Bank of Calcutta and Bank of Bombay, to form the Imperial Bank of India, which in turn became the State Bank of India in 1955. Government of India owned the Imperial Bank of India in 1955, with Reserve Bank of India (India's Central Bank) taking a 60% stake, and renamed it the State Bank of India. In 2008, the government took over the stake held by the Reserve Bank of India. State Bank of India is a banking behemoth and has 20% market share in deposits and loans among Indian commercial banks.

As on 20 January 2017, Government of India held around 62.22% equity shares in SBI. Life Insurance Corporation of India is the largest non-promoter shareholder in the company with 11.27% shareholding. The equity shares of SBI are listed on the Bombay Stock Exchange, where it is a constituent of the BSE SENSEX index,[25] and the National Stock Exchange of India,[26] where it is a constituent of the CNX Nifty. Its Global Depository Receipts (GDRs) are listed on the London Stock Exchange.