Effective Date: December 31, 2021 

The accrued interest calculation in subsection 4803(6) of the IIROC Rules1 , which was illustrated in GN 4800-21-002, is intended for monthly pay instruments that compound interest monthly. 

However, instruments such as NHA mortgaged-backed securities (NHA MBS), compound interest semi-annually. Furthermore, the interest is due on the first day of the month, but is not paid to the investor until mid-month. Consequently, these instruments require a different accrued interest calculation and are exempt from the accrued interest calculation in subsection 4803(6); and therefore, should follow the calculation in Appendix 1. 

• 1In this Guidance, all rule references are to the IIROC Rules unless otherwise specified.