A Practical Guide to Commercial Real Estate Underwriting

Underwriting is the work a lender does to answer one question: will this property produce enough cash to repay this loan, even if things go sideways. Owners and investors often treat it as a black box. It is not. The same handful of numbers decide most commercial real estate files, and you can calculate all of them yourself before you ever send a request to a lender.

Start with net operating income

Net operating income, usually written as NOI, is the income the property produces after operating expenses and before debt payments. Take gross rental income, subtract a vacancy allowance, add other income such as parking or laundry, then subtract operating expenses like taxes, insurance, utilities, management, repairs, and reserves. Do not subtract the mortgage payment, capital improvements, or depreciation.

NOI drives everything else, so underwriters rarely accept your number at face value. They re-underwrite it using market vacancy, market management fees, actual tax bills rather than current ones, and a replacement reserve per unit or per square foot. If your projection is thinner than the market, expect the lender's NOI to come in lower than yours.

Debt service coverage ratio

The debt service coverage ratio, or DSCR, is NOI divided by annual debt service. A property with 120,000 dollars of NOI and 100,000 dollars of annual payments has a DSCR of 1.20, meaning it produces twenty percent more cash than the loan requires. Most lenders want at least 1.20 to 1.25 on stabilized property, and more on riskier asset types or shorter leases.

DSCR is usually the binding constraint on loan size. If the ratio comes in short, the loan amount comes down, the term stretches, or the deal needs more equity. Knowing your DSCR before you apply tells you which of those three conversations you are about to have.

Loan to value and loan to cost

Loan to value, or LTV, is the loan amount divided by the appraised value. Loan to cost, or LTC, is the loan amount divided by total project cost including purchase, construction, soft costs, and carry. Stabilized acquisitions are typically capped near sixty five to seventy five percent LTV. Construction and heavy renovation deals are usually sized on LTC, often near sixty five to eighty percent depending on the lender and the sponsor.

The approved loan is the lowest number the tests produce, not the highest. A file can clear LTV comfortably and still be cut by DSCR, or the reverse. Run all three before you set expectations with a seller or a partner.

Cap rate and value

Divide NOI by the capitalization rate and you get an income based value. At a six percent cap rate, 120,000 dollars of NOI supports a two million dollar valuation. Small changes matter a great deal here: the same NOI at a seven percent cap rate values the property near 1.71 million, which can move a loan by hundreds of thousands of dollars. Use cap rates from recent comparable sales in the same submarket and asset class, not a national average.

The sponsor is part of the file

Lenders underwrite the borrower alongside the property. They look at liquidity after closing, net worth relative to the loan amount, credit history, experience with the same asset type, and the track record of any guarantor. Two identical properties get different answers when one sponsor has done the work before and the other has not. Global cash flow matters too, because losses elsewhere in your portfolio show up in this decision.

Stress testing before the lender does it

Every credit committee asks what happens if the deal underperforms. Model vacancy two or three points above your base case. Raise the interest rate one or two points at refinance. Add a realistic lease up period instead of assuming day one occupancy. Check taxes after reassessment rather than before. If DSCR stays above 1.0 under those conditions, your file is defensible. If it does not, you now know the weak point and can address it in the package rather than letting an underwriter find it for you.

Documents that keep a file moving

Most delays are document delays, not credit problems. Have the rent roll, trailing twelve months of operating statements, two or three years of property and business tax returns, a personal financial statement, leases, the purchase agreement, a scope of work and budget for any construction, and an entity organizational chart ready before you apply. A complete package is the cheapest way to shorten a closing timeline.

Run the numbers yourself

I built underwriting software for exactly this reason: so owners and investors can see NOI, DSCR, LTV, LTC, and stress cases in minutes instead of rebuilding a spreadsheet for every deal.

See how the underwriting software works, or read more about how I help borrowers prepare a financing request.