Banco Central de Sāo Tomé e Príncipe is the central bank, responsible for monetary policy and bank supervision. Six banks are in the country; the largest and oldest is Banco Internacional de São Tomé e Príncipe, which is a subsidiary of Portugal's government-owned Caixa Geral de Depósitos. It had a monopoly on commercial banking until a change in the banking law in 2003 led to the entry of several other banks.