Commercial mortgage underwriting
A full rent roll is not the same thing as durable rent
A rent roll is a snapshot of occupancy and billed economics; the leases are the contracts underneath it. Commercial underwriting tests whether those two layers, actual collections and market evidence describe income that is durable enough to support value and debt.
The rent roll is a summary; the leases create the contractual rights and obligations
A rent roll typically summarizes each unit, tenant, area, rent, lease dates, arrears and other key information. It is useful because it puts the building on one page, but it cannot reproduce every clause that affects economics.
The executed leases establish rent steps, recoveries, options, renewal rights, free-rent periods, termination rights, landlord obligations, assignment rules and other terms that can change the value of the income.
Commercial rent has multiple layers that should not be collapsed into one number
Base rent compensates the landlord for occupancy. Additional rent can include taxes, maintenance, insurance and other recoveries depending on the lease. Collected rent shows what is actually being paid. Market rent estimates what comparable space could command. Effective economic rent can be lower than face rent after concessions.
Underwriting becomes unreliable when the rent roll shows only the highest face-rent number and hides free rent, arrears or unreimbursed landlord costs.
Gross, net and triple-net are economic shorthand, not complete lease analysis
A gross lease can place more operating expenses on the landlord; a net or triple-net structure can shift specified costs to the tenant. The exact drafting controls, not the marketing label.
For NOI, recoveries should be matched with the expenses they are intended to recover. The goal is to understand the landlord’s true recurring economics after the lease allocation of costs.
Concessions can make contractual rent materially higher than economic rent
Free months, tenant-improvement allowances, moving allowances and other incentives can be required to secure a tenant. A five-year lease at $30 per square foot with six months free is not economically identical to five years of uninterrupted $30 rent.
The effect of concessions depends on timing, accounting and valuation methodology, but borrowers should disclose them rather than treating face rent as fully earned from day one.
Lease expiry concentration can turn current occupancy into future refinancing risk
A building that is 100% occupied today can face major rollover if a large share of rent expires in the same year. Underwriting can therefore examine a lease-expiry ladder and, for some assets, weighted-average lease term.
The risk is not just vacancy. Renewal can require downtime, commissions, fit-up, incentives and market-rent resets, all of which affect liquidity and future NOI.
Tenant concentration matters even when total rent is strong
If one tenant generates 60% of building revenue, the property is partly exposed to that tenant’s business and renewal decision. Ten small tenants create different management and turnover risk; neither structure is automatically superior.
The analysis considers tenant quality, business use, remaining term, space re-leasability and the economic cost of replacing the tenant.
Options and special rights can affect both future rent and control of the space
Renewal options, expansion rights, contraction rights, early termination provisions, rights of first refusal and assignment/subletting clauses can change the durability or flexibility of the income stream.
A lease with ten years shown on a summary is not necessarily a ten-year guaranteed income stream if a tenant has an exercisable termination right much earlier.
Estoppel certificates can confirm the tenant’s view of key lease facts
In appropriate transactions, a lender or purchaser may seek tenant estoppels confirming matters such as the lease status, rent, deposits, amendments and known defaults. The exact form and legal effect depend on the documents and transaction.
An estoppel does not replace reading the lease; it can help reconcile whether landlord and tenant understand the current relationship consistently.
Commercial rent can also have GST/HST implications
Commercial rent is generally different from long-term residential rent for GST/HST purposes. Whether tax is charged, collected or recoverable depends on the parties and applicable tax rules.
Mortgage underwriting should keep tax treatment separate from economic rent rather than quietly treating collected tax as property income. Borrowers should obtain accounting or tax advice for their specific structure.
A strong lease review follows the income from contract to market
The most reliable sequence is executed lease → rent roll → concessions/recoveries → actual collections → expiry/options → market-rent evidence → normalized NOI. Each step can explain why the number used for financing differs from the headline rent roll.
Current appraisal standards specifically recognize that existing leases can directly affect value, which is why lease analysis belongs in valuation as well as income underwriting.
Sources and current-rule checks
Sources and verification
Current appraisal, tax and Ontario commercial-tenancy sources support the treatment of leases as economic and legal evidence. Lease obligations are contract-specific, so this page explains underwriting concepts without interpreting any borrower’s lease or providing legal advice.
Canada Mortgage and Housing Corporation
Multi-unit mortgage loan insurance
Verified August 14, 2026
Appraisal Institute of Canada
Canadian Uniform Standards of Professional Appraisal Practice (CUSPAP) 2026
Verified August 19, 2026
Canada Revenue Agency
GST/HST in special cases — commercial leases
Verified August 19, 2026
Government of Ontario
Commercial Tenancies Act, R.S.O. 1990, c. L.7
Verified August 19, 2026