# OSFI Guideline B-20: Fortifying Residential Mortgage Underwriting

> OSFI's B-20 guideline sets the foundation for investment property underwriting.

Category: Investor
Last verified: 2026-04-14
Source: https://ratellow.com/faqs/investor/osfi-guideline-b-20-fortifying-residential-mortgage-underwriting

## Answer
| Rule | Impact on Investment Properties |
|---|---|
| **Stress test qualifying rate is the greater of contract rate + 2% or 5.25%, e.g. for a 4.29% contract rate, qualifying rate is 6.25%** | Reduces qualifying power by ~20% vs contract rate |
| **20% minimum down payment required for investment properties; CMHC insurance is not available for properties over $1,000,000 or investment properties generally** | No CMHC insurance available for most rental properties |
| **Max 80% LTV** | Limits refinancing options for equity extraction |
| **GDS ≤ 39% / TDS ≤ 44%** | Rental income offset (50-80%) helps, but may not be enough |
| **LTI portfolio limits** | Some lenders restricting investor exposure |

Investment properties face stricter scrutiny than primary residences under B-20.

## Related guide
- https://ratellow.com/guides/investment-property-financing-2026

## Sources
- Footnotes — https://www.osfi-bsif.gc.ca/en/guidance/guidance-library/capital-adequacy-requirements-car-guideline-2026
- Disclosure requirements — https://www.osfi-bsif.gc.ca/en/guidance/guidance-library/residential-mortgage-underwriting-practices-procedures-guideline-2017#3.1
- 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