Some lenders see this uncertainty in policy troubling with a couple of examples at Canadian Mortgage Trends Blog.

We talked to some high level folks at the insurers and not even they know what interest rate will be used to qualify borrowes come April 19.It could be the 5-year posted rate or the 5-year discount rate. One source told us it might even be an offset from prime (like prime + 2%).

...

We hate to say it, but these rules seem to have been rushed out with insufficient industry consultation.

And comment on a related post

Qualifying rate: 3.89%

Amortization: 35 years

Maximum Total Debt Service Ratio: 44%

Maximum Gross Debt Service Ratio: 35% (I am using this ratio to give lenders the benefit of the doubt, according to CMHC loan product sheet someone with a credit score over 680 only needs to worry about TDS ratio. See previous post)

Gross Income $100,000

A 35% GDS ratio allows for $2,917 in housing payments including taxes heating and mortgage.

More Assumptions:

Taxes: $280

Heating: $120

=

$2,517 left for monthly mortgage payments.

Maximum mortgage of $580,000, or 5.8x income.

That is with the new rules assuming the discount rate! With a maximum 44% TDS ratio this borrower could potentially be paying an 9% of gross income towards other debts BEFORE taking out this mortgage. That is $750/month!

What are the risks of this? Simply consider the potential of a return to status quo of 2% inflation, slow income growth of 2%/year and a moderate rise in the fixed rate to 7% in 5 years.

In 5 years the mortgage balance is reduced to $536,788, or by 7.5%. At this point it will need to be renewed at a potentially higher rate with 30 year remaining in amortization.

Monthly Mortgage costs renewed @ 7%: $3535

Heating: $132

Taxes: $309

Total Housing Costs: $3976

Monthly Income: $110,408 / 12 = $9201

Gross Debt Service Ratio: 43.2%

Take the possibility the borrower doesn't do much about their other debt situation over 5 years. At renewal 50% of the $750/month debt servicing was interest costs and this is increased by 50% (say from 6% to 9%). In this case other debt payments will increase to $938.

Total Monthly Housing and Debt Costs in 2015: $3976 + $938 = $4914

Total Debt Service Ratio: 53.4%

That's before tax income and even in this fairly mild scenario causes extreme stress to the borrower. I hope this makes the case that qualifying for discount 5-year rates is still too risky to be insured by the CMHC.

...I have to add the obligatory... GO! CANADA! GO!.. hockey game starts in 5 minutes.