A mortgage where the mortgage amount is greater than 80% of the property value (purchase price or appraised value).
Because the borrower has less than 20% equity invested in the property, the loan is considered to be of a higher risk and requires mortgage insurance from a mortgage default insurer (typically CMHC, Sagen, or Canada Guaranty).
Mortgages that are 80% of the property value or less are called Conventional Mortgages.