How to Underwrite Insurance Expense in a CRE Acquisition Pro Forma

Insurance is a modest line in most pro formas and an outsized source of variance. Underwriting it from the seller's current premium is common practice and frequently produces a number that does not survive the first renewal after closing.

It is worth being precise about why this matters. Insurance sits in operating expenses, so every dollar of variance flows directly through net operating income. At a 6 percent cap rate, meaning the rate at which NOI is converted into value, each additional dollar of annual insurance expense reduces valuation by roughly $16.67. A $40,000 miss on a mid sized asset is not a $40,000 problem, it is closer to a $667,000 valuation problem.

Step 1: Treat the seller's premium as information, not as an assumption

Request the seller's declarations page and five year loss runs, the claim history report insurers use to evaluate an account. Both are genuinely useful, though for what they reveal rather than for the number at the bottom.

A seller's premium reflects their program structure, their portfolio scale, their loss history, and often market conditions from when the policy was written. Very little of that transfers with the deed. A low premium sometimes reflects a low insured value, a high CAT deductible, or missing coverage you would not choose to replicate.

Step 2: Establish the correct insured value

Underwrite the building at current replacement cost, not at purchase price and not at the seller's stated value. Purchase price includes land and reflects income, neither of which relates to what it costs to rebuild a structure.

The relationship between insured value and true rebuild cost is called insurance to value, or ITV. Given how much construction costs have moved recently, a seller's figure that has not been refreshed is likely low, and correcting it will raise the premium regardless of market direction.

Step 3: Price the actual risk profile

The variables driving commercial property premium are reasonably consistent:

• Construction type and year built
• Roof age and condition
• Location, including wind, hail, wildfire, and flood exposure
• Occupancy type and tenant mix
• Protective features such as sprinklers and alarms
• Loss history at the property

CAT exposure deserves specific attention because it drives both rate and deductible structure. A percentage based named storm deductible is a balance sheet item as much as an expense item, and it belongs somewhere in your model.

Step 4: Build the estimate

The standard approach is a rate per $100 of TIV. TIV means total insured value, the sum of building, contents, and business income values across the asset, and it is how insurers describe the size of an account. A property with $10 million TIV priced at a rate of $0.35 produces a $35,000 property premium. Cost per square foot works as a cross check.

Comparable properties in the same market and asset class are the best reference point. Portfolio owners can often draw on their own recent placements, which tends to be more reliable than published averages.

Where the property will be added to an existing master program or blanket policy, meaning a single program covering multiple locations under shared limits, model the incremental cost rather than a standalone premium. Scale frequently changes the answer materially.

Step 5: Include what is easy to omit

Property premium is only part of the line. Depending on the asset and structure, full insurance expense may also include general liability, umbrella or excess liability, equipment breakdown, terrorism coverage under TRIA, flood or earthquake where applicable, and environmental coverage.

Retained risk belongs in the model as well. Retained risk is the portion of loss you absorb yourself, primarily through deductibles. A property with a 5 percent named storm deductible carries a meaningful retained exposure that belongs in your downside case, not only in the risk narrative.

Step 6: Trend forward and test the assumption

Insurance is not a flat line expense. Model annual growth reflecting both rate movement and rising replacement costs, then stress test it. If a 15 to 20 percent increase in insurance expense materially changes your returns or your debt service coverage, that is worth knowing before closing.

Common underwriting errors

• Using the seller's premium unchanged
• Insuring to purchase price rather than replacement cost
• Omitting CAT deductible exposure from the downside case
• Assuming flat renewals across the hold period
• Modeling property premium alone and omitting liability and specialty lines

What this means for you

Insurance expense is one of the more forecastable lines in a pro forma once it is built from the property's actual characteristics rather than inherited from the seller. The work is modest, and it removes a variable that otherwise tends to surface at the least convenient point in the hold period.