Total bond issued is reported by BIS debt securities data. Let BIS denote this amount.
Bonds held by foreign investors is reported by Balance of payment statistics (IMF). It is the portfolio debt foreign liabilities on balance of payment of issuing countries. Let L_DS denote this amount.
My question is: why are there so many times L_DS>BIS?
Example of the United Kingdom is shown below. x=BIS-L_DS It is below zero all the time.