What you should know about the new mortgage rules. On October 3rd, Finance Minister Bill Morneau announced that new mortgage rules will include more stringent “stress testing” for borrowers. These rules are designed to lower debt levels, enforce some belt-tightening, and protect the housing market over the long term. Here’s how these new mortgage rules will affect Canadians. THE HIGH-RATIO RULE There has been a long-time rule that you must have “high-ratio mortgage insurance” if you have less