What Really Happens Behind Your Approval.
Underwriting is the part of the mortgage process most people never see — the careful review a lender does before agreeing to lend. Here it is in plain English: what an underwriter looks at, the conditions they may ask for, and how pre-approval, conditional approval and final approval actually differ.
What mortgage underwriting is
The lender's assessment of risk before agreeing to advance funds.
Mortgage underwriting is the process a lender uses to decide whether — and on what terms — it is comfortable lending against a specific property to a specific borrower. An underwriter reviews your application and supporting documents to answer a few core questions: can this borrower reasonably afford the payments, is the income and employment stable, is the credit history reliable, is the down payment genuine, and does the property itself provide adequate security for the loan?
It matters because the mortgage is a large, long-term commitment for both sides. The underwriter's job is to weigh the strengths and risks in a file against the lender's guidelines and applicable regulatory requirements. Every lender sets its own policies, so the same file can be viewed differently from one lender to the next.
This page is general information only. It is not mortgage advice, an approval, or a commitment to lend. Final lending decisions rest with the lender and depend on the borrower, the property, the documentation provided and each lender's guidelines.
What an underwriter reviews
Six areas that shape almost every decision.
Income verification
Confirming that the income used to qualify is real, documented and reasonably expected to continue.
Employment stability
How long you have worked, the type of income, and whether your employment situation looks steady.
Credit history
Your track record of managing debt — score, payment history and how much of your available credit you use.
Down payment & source of funds
Confirming you have the funds to close and that they come from an acceptable, traceable source.
Property value & appraisal
Whether the property provides adequate security, sometimes confirmed through an appraisal.
Debt-service ratios
How your housing costs and total debts compare to your income — the GDS and TDS measures.
Income verification
Underwriters want to see that the income used to qualify is genuine and likely to continue. The documents requested depend on how you are paid. Salaried and hourly employees are usually asked to confirm employment and earnings, while self-employed borrowers typically document income through their tax filings and business records.
Amounts, formats and acceptable proof vary by lender and by income type. Providing complete, current and consistent documentation up front tends to make the review smoother.
Summarize employment income reported for a tax year.
Show current earnings, pay frequency and year-to-date totals.
The CRA's confirmation of income filed and any taxes owing.
Your full personal tax return, often requested for self-employed or variable income.
General financial statements for self-employed and incorporated borrowers.
Employment stability
Beyond the dollar amount, underwriters consider how dependable the income is. Longer tenure in the same role or field generally reads as more stable, while very new employment or a probationary period may prompt additional questions or documentation.
The type of income matters too. Guaranteed base salary is viewed differently than income that varies — such as commission, bonus, overtime, part-time or contract earnings — which lenders often want to see established over a period of time.
How long you have been with your employer or in your line of work.
New roles or probationary periods may need extra confirmation.
Salaried, hourly, commission, bonus, contract or self-employed are each assessed differently.
Variable income is often reviewed over time to establish a reliable pattern.
Credit history
Your credit report tells the underwriter how you have handled borrowing in the past. They look at more than the number: payment history shows whether you pay on time, while credit utilization — how much of your available credit you are using — signals how you manage revolving debt like credit cards and lines of credit.
A strong, consistent history generally supports an application. Missed payments, collections or heavy utilization can raise questions. Guidelines around credit differ by lender and lending type.
Want to understand the score itself? See our guide to credit scores.
A snapshot of overall credit risk at a point in time.
Whether payments have been made on time and as agreed.
How much of your available revolving credit you are currently using.
Length of history and the range of credit you have managed.
Down payment & source of funds
Underwriters confirm not only that you have the down payment and closing funds, but where those funds came from. This is a standard part of anti-money-laundering and lender due diligence, so it applies to everyone — it is not a reflection on you.
As a general concept, lenders often want to see the money's history over a recent period — commonly described as a roughly 90-day trail — to confirm it is your own accumulated savings or another acceptable source. Where funds are gifted by an immediate family member, a signed gift letter is typically required. Exact requirements vary by lender and by the source of the funds.
Statements showing accumulated funds and their movement over time.
Confirmation that gifted funds are genuine and not repayable, where a gift is used.
A general trail — often around 90 days — showing where the funds originated.
Underwriters may ask about unusual or large deposits to confirm the source.
Property value & appraisal
The property is the lender's security, so its value matters as much as your finances. A lender may require an appraisal to confirm the property is worth what is being paid and is suitable to lend against. In some cases a lender may accept an automated or lender-side valuation instead; in others a full appraisal is requested.
Whether an appraisal is needed, and who arranges it, depends on the property, the transaction and the lender's guidelines.
Learn more in our guide to home appraisals.
An appraisal helps confirm the property supports the loan amount.
Condition, type and location can all factor into a lender's view.
Some files require a full appraisal; others may rely on a lender valuation.
Debt-service ratios: GDS & TDS
Gross Debt Service (GDS)
GDS compares your expected housing costs — generally mortgage payment, property taxes, heating and, where applicable, a portion of condo fees — to your gross income. It answers a simple question: how much of your income would the home itself consume?
Total Debt Service (TDS)
TDS goes further and adds your other debt obligations — such as car loans, credit cards and lines of credit — to those housing costs, again measured against your gross income. It reflects the full picture of what you owe.
How the guidelines work
Lenders apply maximum ratio guidelines, so lower is generally better. As a general illustration only, GDS limits are often described in a range around the mid-to-high 30s percent of gross income, and TDS limits somewhat higher — but the specific thresholds, and any flexibility, depend on the lender, the program and the borrower's overall profile.
These figures are illustrative and change over time; they are not a promise of what you will qualify for.
Conditions that may be requested
Common items a lender may ask for while reviewing a file.
More recent pay stubs, an employment letter or updated tax documents.
Statements confirming the funds to close and their source.
An appraisal or valuation of the property being financed.
A letter confirming your position, tenure and income.
Clarification of large deposits, credit items or gaps.
Confirmation of property information and, where applicable, proof of home insurance.
Pre-approval vs conditional approval vs final approval
Three very different stages that are easy to confuse.
Pre-approval
An early estimate of what you may be able to borrow, often paired with a rate hold for a set period. It helps you set a budget and shop with confidence — but it is based on preliminary information and is not a guarantee of financing. Full underwriting still happens later, and a specific property has not yet been assessed.
Conditional approval
After a full application on a specific property, a lender may issue an approval that is subject to conditions — the outstanding items the underwriter still needs, such as documents, confirmation of the down payment or an appraisal. The approval stands only if those conditions are met to the lender's satisfaction.
Final approval & funding
Once all conditions are satisfied and reviewed, the file can move to final approval and, on closing, the lender advances the funds. This is the point at which the mortgage is genuinely in place.
How GNE Mortgages Handles Underwriting
Working through GNE Mortgages, you have in-house underwriting support behind your file. Rather than sending an application off and hoping for the best, the goal is to prepare it properly the first time.
Going through the application in detail before it reaches a lender.
Spotting missing or problematic items before they become obstacles.
Explaining what a lender is asking for, and why, in plain language.
Presenting a complete, organized file that reflects your situation accurately.
Addressing common gaps up front so the review is not held up by preventable issues.
This support does not guarantee approval or a turnaround time. Final lending decisions remain with the lender and depend on the borrower, the property, the documentation provided and each lender's guidelines.
Related pages
Mortgage Qualification
How lenders decide what you can borrow, and the factors that shape it.
Debt Servicing: GDS & TDS
A closer look at the ratios lenders use to measure affordability.
Mortgage Pre-Approval
What a pre-approval is, what it is not, and how to use one.
Required Documents
The paperwork lenders commonly ask for during underwriting.
Have a file you want reviewed properly?
Book a call and we'll walk through what a lender will look for.