BTW - the fictitious calendar is very often used in bond repayments - e.g. https://www.lawinsider.com/dictionary/bond-payment-dates https://www.lawinsider.com/d

BTW - the fictitious calendar is very often used in bond repayments - e.g. https://www.lawinsider.com/dictionary/bond-payment-dates https://www.lawinsider.com/dictionary/bond-payment-dates It has historically been used to allow for bonds to have uniform repayments across maturities (when the principal of a bond becomes due) - useful in the context of a bank wanting to hedge risks such as interest rate risk, repayment risk (if the bond is callable it can be paid back early, which means the bondholders have cash yielding ~0% instead of whatever the bond yield was) Mortgages, though not traditional bonds (in that it's not a sophisticated company borrowing) are, depending on the jurisdiction, treated as bonds because they get packaged up and sold as bonds - the underlying bit of financial engineering that, after serious perversion, gave us the 2008 credit crisis