In the national banking system of the United States, any of certain cities in which the national banks are required (U. S. Rev. Stat. sec. 5191) to keep a larger reserve (25 per cent) than the minimum (15 per cent) required of all other banks. The banks in certain of the reserve cities (specifically called central reserve cities) are required to keep their reserve on hand in cash; banks in other reserve cities may keep half of their reserve as deposits in these banks (U. S. Rev. Stat. sec. 5195).