IHTM27091 - Foreign property: debts: contractual
In English law a simple contract debt is situated where the debtor resides: Att Gen v Bouwens (1838) 4 M & W 171, English, Scottish and Australian Bank Ltd v IRC [1932) AC 238. That means that where the debtor was resident in the UK at the date of the chargeable transfer the debt is chargeable to Inheritance Tax.
A debt under a letter of credit has been held to be situated in the place where it is in fact payable against documents (Power Curber International Ltd v National Bank of Kuwait [1981] 3 A11 ER 607).
Corporation mortgages, issued by local authorities under seal, and Northern Irish Land Bonds are examples of specialty debts. You should be careful not to confuse corporation mortgages with corporation stock, which is far more common and which is a registered security, situated where the register is kept.