The client
A household in Shawinigan ported a $285,000 insured mortgage to a $402,000 purchase, topping up the balance by $68,000 for the price difference.
Ported balance
$285,000
Existing insured mortgage, carried across unchanged
Top-up amount
$68,000
Financing the price difference on the new, pricier purchase
New purchase price
$402,000, Shawinigan
Original closing date
Late December 2026
Slipped a few business days into January 2027
The problem
Porting an insured mortgage to a pricier new property can bring a top-up premium on the incremental amount -- priced by the insurer, not recalculated on the whole balance. Quebec then applies its own tax to that premium, at whatever rate is in force on the date the premium is actually charged.
Why the date, not the deal, decided the tax
- ▸The top-up premium itself was priced correctly, on the $68,000 increase alone, when the port was first arranged in December 2026
- ▸Quebec's insurance-premium tax rate was legislated to rise from 9% to 9.975% effective January 1, 2027 -- a change already on the books when the file was quoted
- ▸The closing slipped a few business days for ordinary reasons, landing the actual funding date on the far side of that legislated boundary
Nobody mispriced anything. The calendar simply moved the file from one tax rate into the next.
The numbers
Once the top-up premium itself was set, the only open question was which of the two legislated tax rates would apply on the day it was actually charged.
| The top-up premium's own insurance tax, either side of January 1 | Amount |
|---|---|
| Top-up premium (6.10% of the $68,000 increase) | $4,148 |
| Tax at 9% (in force through Dec 31, 2026) | $373 |
| Tax at 9.975% (in force from Jan 1, 2027) | $414 |
| Total debt service on the ported-plus-topped-up balance | Figure |
|---|---|
| Payment at the qualifying rate (6.90%), 25 years | $2,451/mo |
| Property tax | $335/mo |
| Heat (lender estimate) | $125/mo |
| GDS | 30.3% |
| TDS (incl. car loan) | 33.0% |
30.3% GDS and 33.0% TDS were never in question on this file. The $41 gap between the two tax figures was small in dollars, but the lesson scales with the size of any top-up premium a broker prices near a legislated rate-change date -- and Quebec's welcome tax on the new $402,000 purchase, $4,140, was owed regardless of which side of January 1 the premium itself landed on.
The solution
A courtier hypothécaire licensed under Quebec's Act respecting the distribution of financial products and services treated the tax on the top-up premium as a funding-date question, not a commitment-date one.
First, confirmed with the insurer that the tax is calculated against the premium's actual funding date, not the date the port and top-up were originally quoted. The commitment letter's own cost estimate had used the pre-2027 rate.
Second, re-quoted the closing-cost cash requirement against the realistic expected funding date once the closing slipped, rather than letting the client discover the higher figure at the lawyer's trust ledger.
Third, kept the top-up premium calculation itself unchanged -- only the tax rate applied to it moved, since the premium is priced on the increment at the time the port and top-up are arranged.
The outcome
The port and top-up funded at 4.90%, at 30.3% GDS and 33.0% TDS, with the top-up premium's own insurance tax landing at $414 once funding fell in January 2027.
Both ratios sit comfortably inside CMHC's 39%/44% maximums; the file was never at risk on the numbers -- only the tax line item moved, and only because of the date.
What to take from this file
- 01Quebec's tax on an insurance premium is set by the date the premium is actually charged, not the date a deal is arranged. A closing that slips across a legislated rate-change date changes the tax bill, not the premium itself.
- 02A top-up premium on a port is priced on the increment, not the whole balance. Keep that calculation separate from whatever tax rate happens to apply on the funding date.
- 03Re-quote closing costs against the realistic funding date whenever a closing slips near a known rate-change boundary. A commitment-date estimate can go stale for reasons that have nothing to do with the mortgage itself.
- 04The dollar amount can be small, but the principle scales. A larger top-up premium crossing the same boundary produces a proportionally larger, equally avoidable surprise.
Sources
Every regulatory figure in this file traces to one of these primary sources. Client details and anything that varies by lender are illustrative, as flagged below.
- ▸OSFI — Minimum qualifying rate for uninsured mortgages — the minimum qualifying rate — greater of contract rate + 2% or 5.25%.
- ▸CMHC — CMHC Reviews Underwriting Criteria — GDS 39% / TDS 44% maximums and the 600 credit-score floor for insured files.
- ▸Provincial/territorial mortgage-broker legislation fetched directly (bclaws.gov.bc.ca, legisquebec.gouv.qc.ca, fcaa.gov.sk.ca, web2.gov.mb.ca, nslegislature.ca, assembly.nl.ca) plus FCNB's own site for NB and CanLII's index for PE — see notes for per-province method — provincial mortgage regulators and licence titles.
- ▸Gouvernement du Québec — Droits sur les mutations immobilières — Quebec's transfer duties ('welcome tax') — 2026 indexed brackets.
- ▸Act respecting the Québec sales tax, CQLR c. T-0.1, Title III ("Taxation of Insurance Premiums"), ss. 507, 512, 520 — Quebec's 9% tax on insurance premiums (rising to 9.975% in 2027).
Illustrative in this file — lender-specific, not rules:
- ▸4.90% contract rate — rates move daily; not a quote.
- ▸6.10% top-up premium rate — Sagen's own published top-up band is 5.90%-6.30%; the exact figure a file draws depends on the specific insurer and file, not a fixed rule.
Authority & provenance
How this case file was built
We publish the origin, the verification method and the reviewer for every case file, so you can judge how far to trust it before you rely on it with a client.
Where it comes from
Derived from files handled by Treadstone’s fulfillment desk and from scenarios contributed by partner brokerages. Names, employers, exact amounts and dates are changed so no client or file is identifiable.
Provenance: Composite — a pattern seen repeatedly on fulfilled files, not a single transaction.
What is verified
Every regulatory figure traces to a primary source listed above and was checked against it on the date shown. The arithmetic is recomputed by machine on every rebuild.
Anything that varies by lender is labelled illustrative rather than stated as a rule.
Who reviewed it
Reviewed for Canadian regulatory accuracy before publication, and re-checked whenever a cited rule changes.
Reviewed by: Nicholas Parson, Treadstone Associates — reviews every case file before publication.
This case file is professional reference material for licensed mortgage professionals. It is not advice to a borrower, and it is not a lender commitment. Insurer rules, qualifying rates and provincial taxes change — confirm the current position with the insurer, regulator or lender before you rely on any figure here in a live file.