State Bank of India is an Indian multinational, Public Sector banking and financial services company. It is a government-owned corporation with its headquarters in Mumbai, Maharashtra. As of December 2013, it had assets of US$388 billion and 17,000 branches, including 190 foreign offices, making it the largest banking and financial services company in India by assets. State Bank of India is one of the Big Four banks of India, along with Bank of Baroda, Punjab National Bank and ICICI Bank. 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. 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 regional banking behemoth and has 20% market share in deposits and loans among Indian commercial banks.