Key takeaways
- →There are three pricing buckets, not two: insured (borrower-paid, under 20% down), insurable (uninsured but still meets insurer eligibility, lender-paid bulk insurance), and uninsurable (meets neither set of criteria).
- →A lender can purchase portfolio (bulk) insurance on an otherwise-uninsured file that still meets an insurer's eligibility criteria, lowering its own funding cost even though the borrower doesn't pay the premium directly.
- →Refinances are always excluded from mortgage default insurance eligibility, regardless of loan-to-value — making every refinance uninsurable by definition, not just uninsured.
- →Uninsurable mortgages typically carry the highest rate of the three buckets, because the lender holds the full default risk with no insurer backstop at all.
Ask most brokers where the line falls between an insured and an uninsured mortgage, and they'll get to 20% down correctly. Ask why two uninsured files at the same lender sometimes price differently, and the answer usually stalls — because there's a third bucket most brokers have never had explained clearly.
This isn't a rehash of the insured/uninsured ratio rules — for the GDS/TDS and amortization mechanics on that side of the line, see our companion piece on insured vs. uninsured underwriting. This is about the funding-cost split underneath: insured, insurable, and uninsurable, and why a lender's rate sheet reflects all three.
01 · Why are there three pricing buckets, not just insured and uninsured?
Insured describes a mortgage where the borrower pays the default insurance premium directly — required whenever the down payment is below 20%. But among mortgages with 20% or more down, there's a further split most clients never hear about: some of those uninsured files still meet an insurer's eligibility criteria, and some don't.
The ones that still qualify are “insurable” — the lender, not the borrower, can purchase insurance on them. The ones that don't qualify under any structure are “uninsurable.” Same 20%-or-more down payment on paper, two very different funding pictures underneath.
02 · What makes an uninsured file 'insurable' rather than 'uninsurable'?
Broadly the same eligibility criteria that apply to insured mortgages — owner-occupied property, purchase price under the insured price cap, amortization within standard limits — even though the borrower isn't the one paying the premium. Under OSFI's Guideline B-21, which governs how federally regulated mortgage insurers underwrite this risk, a lender can pool eligible uninsured mortgages and purchase what's known as portfolio or bulk insurance on them.
That purchase lowers the lender's own cost of funding the loan, since the insurer is now backstopping default risk on that file even though the borrower never applied for coverage directly — and a lender with more of its book placed into insurable buckets can pass some of that funding advantage through in its posted rates.
03 · Why do uninsurable mortgages usually carry the highest rate of the three?
Because there's no insurer backstop anywhere in the structure — the lender carries the full default risk itself, with no bulk-insurance option to offset its funding cost the way it can on an insurable file.
| Bucket | Who pays the premium | Example files |
|---|---|---|
| Insured | Borrower | Under 20% down, owner-occupied, under the insured price cap |
| Insurable | Lender (portfolio/bulk insurance) | 20%+ down, but still meets insurer eligibility criteria |
| Uninsurable | No one — lender holds full risk | Refinances, rentals/non-owner-occupied, above the insured price cap or standard amortization limits |
Refinances fall into the uninsurable bucket categorically, regardless of loan-to-value — they're excluded from mortgage default insurance eligibility entirely under the current federal rules, which is part of why refinance rates often sit apart from purchase rates on the same lender's sheet.
04 · What does the insured/insurable/uninsurable split change about how a broker chooses a lender?
It explains a pattern brokers see constantly without always naming it: two lenders quoting different rates on the same uninsured file, because one can place more of that file type into an insurable bucket than the other can, given its own book and funding structure.
Understanding which bucket a file actually falls into — before shopping it to lenders — is exactly the kind of underwriting-adjacent judgment Treadstone's AI mortgage underwriting early-access program is designed to support.
Know the bucket before you shop the file
See the pricing logic before it shows up as a rate quote.
Treadstone's Engage AI underwriting reads a file's insured, insurable, or uninsurable status early, so brokers know what they're actually shopping before it reaches a lender.
Frequently asked questions
This article is general information to help you scale — not a substitute for tailored advice on your specific business, licensing, or compliance obligations. All figures are illustrative examples for planning purposes; actual costs vary by province, market, and brokerage.