How Commercial Mortgage Underwriting Works

Commercial mortgage underwriting is the process a lender uses to decide whether the income from a property, and the strength of the borrower behind it, can safely cover the loan repayments and clear the debt over the term. Underwriters are not testing whether the building is nice; they are testing whether the cash coming in comfortably exceeds the cash going out, and whether the loan is well covered if values or income slip. Get those two questions answered convincingly on paper and most of the work is done. We are a broker, so we do not underwrite or price anything ourselves; what we do is read the case the way an underwriter will, then place it with a lender whose criteria actually fit.

The first number an underwriter builds is the debt service cover ratio (DSCR), sometimes called rental or income cover. It is simply the net income available to service the loan divided by the annual loan cost. Most commercial lenders want to see cover comfortably above 1, and for investment property a stressed cover of around 125% to 145% is a common indicative expectation, meaning income must exceed the interest at a stressed rate by that margin. The exact hurdle, the stress rate, and whether they use interest-only or a capital-and-interest cost all vary by lender and by the property, so treat any number here as illustrative rather than a rule.

Loan to value (LTV) is the second pillar. It is the loan set against the lender's valuation, not your purchase price or your optimistic estimate, and the valuer's figure is what governs. Indicatively, owner-occupied commercial mortgages often reach up to around 70% to 75% LTV, while investment property tends to sit a little lower, frequently 65% to 75%, with specialist or weaker-covenant cases lower still. Where DSCR and LTV disagree, the lower of the two wins; strong cover will not rescue a stretched LTV, and a low LTV will not rescue thin income cover.

Whether the deal is owner-occupied or investment changes what the underwriter scrutinises. On an owner-occupied case (your trading business buying its own premises), the underwriter leans on your business accounts: turnover, profitability, EBITDA or adjusted profit, and whether the trading cash flow can service the mortgage on top of everything else the business pays for. On an investment case, the focus shifts to the lease. Underwriters look hard at tenant strength (the covenant), the unexpired lease term, break clauses, and any voids or arrears. A long lease to a strong, established tenant is worth far more to a lender than a short lease to an unknown one, because it makes the income look durable.

Behind the property sits the borrower covenant, meaning you and, for a limited company, its directors and shareholders. Underwriters will review filed accounts and often management figures, look for a clean or explained credit history, and usually expect a personal guarantee from the principals on a limited-company loan. They are checking that if income dips, someone with visible means stands behind the debt. Adverse credit, recent losses, or a very new company do not automatically stop a deal, but they narrow the pool of lenders and tend to move pricing and LTV; the lender decides how it treats them.

Property type is the quiet variable that shapes everything else. Standard offices, industrial units, warehouses, and retail on established terms are the most straightforward. Specialist assets (care homes, pubs, petrol stations, HMOs run as commercial, leisure) are valued partly on the business that runs them, which fewer lenders will touch and usually at lower LTV and higher rates. Underwriters also weigh location, condition, marketability if they ever had to sell, and any environmental or planning flags. The more specialist the asset, the more the right lender choice matters.

How you present the case genuinely changes the outcome. A clean file with up-to-date accounts, a clear rent schedule or trading summary, tenancy agreements, a plain explanation of the purchase or refinance rationale, and an honest note on any blemish lets an underwriter say yes quickly. A thin or contradictory file invites more questions, more caution, and a lower offer. This is where our broker role earns its place: we tell you fast which lenders are realistically open to your property type, income profile, and covenant, package the numbers the way underwriters read them, and put the case in front of the right desk. We cannot promise a rate, an LTV, or an approval before a lender has seen your file; those decisions and the pricing are always the lender's, on your specific case.