Purchase money security interests (PMSIs) are perfected by special rules. These are called the PMSI Rules in this book.

The PMSI Rules¹, which apply to all PMSIs both strong PMSIs (conditional sales by way of retention of title, commercial consignments and PPS Leases) and normal PMSIs, are that:

1. 1. perfection must be by registration;
   2. the registration must nominate that the security interest is a PMSI;
   3. where the collateral is inventory the PMSI must be registered before the collateral is either supplied to the grantor (for inventory that is goods), or the security interest attaches (for other inventory):
   4. where the collateral is equipment (not inventory), the PMSI must be registered within 15 business days of the secured party supplying goods to the grantor, or 15 business days of the security interest attaching for collateral other than goods.