6.1 This chapter covers sources of data on transactions and positions in external financial assets and liabilities of the general government and the central bank sectors.1 These transactions and positions can have a significant impact on the balance of payments; therefore, their measurement requires careful attention. The chapter also examines data (which may be relevant to the balance of payments) gathered by government sector institutions as a by-product of carrying out their various functions. Examples are data from applications to invest, to acquire foreign exchange, and to export, and data from taxation, education, and health authorities.