# How does OSFI's B-20 guideline influence mortgage underwriting practices?

> OSFI's Guideline B-20 sets expectations for prudent residential mortgage underwriting for Federally Regulated Financial Institutions (FRFIs).

Category: Strategy
Last verified: 2026-04-14
Source: https://ratellow.com/faqs/strategy/how-does-osfis-b-20-guideline-influence-mortgage-underwriting-practices

## Answer
OSFI's Guideline B-20 sets expectations for prudent residential mortgage underwriting for Federally Regulated Financial Institutions (FRFIs). It emphasizes assessing a borrower's willingness and capacity to service their debt obligations, supported by sound collateral management and risk management practices. It's about protecting lenders and borrowers!

## Institutional highlights
- Your lender must follow strict rules when approving your mortgage.
- Lenders should look at your whole financial picture when deciding if you qualify for a mortgage.
- Mortgage lenders have to share details about the mortgages they've issued.
- If your mortgage is considered higher risk, your lender will have extra checks and balances in place.
- You can only borrow up to 80% of your home's value with a Home Equity Line of Credit (HELOC) that doesn't require regular payments.

## Related guide
- https://ratellow.com/guides/mortgage-prepayment-privileges

## Sources
- I. Purpose and scope of the guideline — https://www.osfi-bsif.gc.ca/en/guidance/guidance-library/residential-mortgage-underwriting-practices-procedures-guideline-2017#1.0
- Mortgage Insurance Prepay and Re-Advance Policy — https://www.sagen.ca/ups/underwriting-documentation/#mortgage-insurance-prepay-and-re-advance-policy-638f55989d20b
- Disclosure requirements — https://www.osfi-bsif.gc.ca/en/guidance/guidance-library/residential-mortgage-underwriting-practices-procedures-guideline-2017#3.1