Treadstone Associates
Case File № 137 · Renewals & Switches

Quantifying the shock

a 2022-vintage fixed cohort renews into a higher-rate market

A Cranbrook borrower's 2022-vintage fixed rate matured into a materially higher-rate market: a $365-a-month, 20.4% payment shock. A straight switch avoided the minimum qualifying rate, which would otherwise have pushed TDS to 46.7% — over the ceiling.

British ColumbiaUninsured · straight switchFiled August 7, 20265 min read
+$365/mo

Payment shock — the same balance and amortization, four years later

41.3%

TDS at the actual switch rate, thanks to the exemption

46.7%

What TDS would have been at the minimum qualifying rate — over the ceiling

Anonymized illustration. The borrowers, dollar figures, and rates in this file are an illustrative composite — no real client is identifiable, and any rate shown is illustrative, not a quote. The rules are real: every regulatory figure is cited to its source in the Sources section, and the math computes exactly as shown.

№ 01

The client

A homeowner in the Cranbrook market locked in a 4-year fixed rate in 2022, near the bottom of that rate cycle, ahead of the 2026 renewal wave now working through the system. Renewing in 2026 into a materially higher-rate market, as tracked in the stress-test qualifying-rate history, meant the payment increase was not a rumour — it was a number that had to be qualified for, using the same payment-increases-at-renewal data brokers are seeing across the country.

Mortgage balance at maturity

$328,000

21 years remaining amortization

2022 contract rate

3.24%

Held constant for comparison

2026 switch rate

5.34%

Straight switch, same balance and amortization

Applicant income

$6,900/month

Used in both TDS checks below

Existing debt

$250/month

Carried into the TDS check

Holding the balance and amortization fixed isolates exactly what the rate change alone did to the payment:

Payment at each rateMonthly
At the 2022 rate (3.24%), held constant$1,792
At the 2026 switch rate (5.34%)$2,157
Payment shock+$365/mo
№ 02

The problem

The rate increase alone was real and unavoidable — a $365-a-month, 20.4% jump on the identical balance and amortization, or $4,380 a year. What decided whether the file actually qualified, though, was not the payment shock itself but whether the switch had to be tested against the minimum qualifying rate on top of it.

Why the switch avoided the stress test

  • Same $328,000 balance, same 21-year remaining amortization — no increase on either
  • Federally regulated lender to federally regulated lender
  • Both conditions of OSFI's exemption for uninsured straight switches are met, so the minimum qualifying rate of 7.34% does not apply

Had this not qualified as a straight switch, the borrower would have needed to qualify at the 7.34% minimum rate on top of already absorbing the real payment shock — a materially harder test than the one the exemption actually applies.

№ 03

The numbers

The payment shock and the stress-test comparison are two separate numbers, and only one of them determines whether the file qualifies.

Quantifying the shockAmount
Payment at the 2022 rate, held constant$1,792
Payment at the 2026 switch rate$2,157
Monthly payment shock$365
Payment shock as a percentage of the 2022 payment20.4%
Annualized shock$4,380

Qualifying at the actual rate, thanks to the exemption

TDSAt the 5.34% actual rateAt the 7.34% minimum qualifying rate (hypothetical)
Housing costs (P&I, tax, heat)$2,597$2,974
Other debt$250$250
TDS41.3%  ✓46.7%  ✗

The exemption is the entire difference between this file qualifying and failing. At the actual switch rate, TDS clears comfortably at 41.3%; had the minimum qualifying rate applied, the same borrower would have failed at 46.7%, despite genuinely affording the real payment.

№ 04

The solution

A submortgage broker licensed under BCFSA confirmed both conditions of the exemption before quoting the client anything — the balance and amortization could not increase by even a small amount, or the exemption, and the qualification path with it, would disappear.

The submission documented the shock transparently rather than downplaying it, since the client needed to understand the real payment increase regardless of which qualifying rate applied:

Existing mortgage statement confirming the 2022 balance and rate
Written confirmation from both lenders of federally regulated status
Confirmation the new balance and amortization exactly match the existing loan
Two years of T4s and NOAs supporting the $6,900 income
Side-by-side payment comparison for the client's own decision

Explaining the mechanics up front — that the exemption depends entirely on the loan amount and amortization not increasing — meant the client understood the payment shock was real and unavoidable, while the qualification path around it was not automatic.

№ 05

The outcome

Approved and funded: $328,000 straight switch at 5.34%, same 21-year remaining amortization, qualifying at the actual rate under the OSFI exemption rather than at 7.34%.

As a switch rather than a purchase, no property transfer tax applies; the only cost was the new lender's standard switch administration fee, quoted separately and not itemized as a dollar figure here.

№ 06

What to take from this file

  • 01Quantify the payment shock explicitly, in dollars and as a percentage. A $365-a-month, 20.4% increase is a concrete number a client can plan around; a vague warning that rates have gone up is not.
  • 02The straight-switch exemption is the difference between qualifying and not, not just a paperwork shortcut. This file passes at 41.3% on the actual rate and fails at 46.7% at the minimum qualifying rate.
  • 03Confirm both exemption conditions before quoting a rate. Any increase in balance or amortization, and the file would have needed the harder stress-test qualification instead.
  • 04A payment shock and a stress-test failure are two different risks. This borrower could afford the real 2026 payment easily; only the hypothetical stress-tested payment would have failed.

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.

Illustrative in this file — lender-specific, not rules:

  • 3.24% / 5.34% rates — rates move daily and vary by term; not quotes.
  • $300/mo tax and $140/mo heat estimates — lender-standard estimates, not rules.

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.

First published 7 August 2026Rules last verified 7 August 2026Next scheduled review 7 February 2027

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.

Treadstone fulfillment

Files like this are daily work for our desk.

Document collection, ratio math under multiple treatments, lender placement notes, and submission-ready packaging — for Canadian mortgage brokers who would rather be in front of clients.