The State Bank of Pakistan (SBP; Urdu: بینک دولت پاکستان‎) is the central bank of Pakistan. While its constitution, as originally laid down in the State Bank of Pakistan Order 1948, remained basically unchanged until January 1, 1974, when the bank was nationalized, the scope of its functions was considerably enlarged. The State Bank of Pakistan Act 1956,[2] with subsequent amendments, forms the basis of its operations today. The headquarters are located in the financial capital of Pakistan, Karachi with branch offices in 15 cities across Pakistan, including the capital city, Islamabad and the four provincial capitals.