328. Data sources available from the official sector (the general government sector and the monetary authorities) are examined in chapter 8. The chapter covers sources of data on own-account transactions and stocks of external financial assets and liabilities of the general government sector and the monetary authorities.56 These transactions can have a significant impact on the BOP; therefore, their measurement requires careful attention. The chapter also examines data (which may be relevant to the BOP) gathered by official 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.