Tax
Cost segregation
An engineering study that reclassifies parts of a building into shorter depreciation lives.
This page defines one term. If you have arrived here from a listing or a broker's summary, the useful order is: read what it is, then read what it does not tell you, and only then look at the number you were quoted. What would mislead: any single measure on a property is a summary of one year, one assumption or one document. None of them describes a whole investment, and the misreading section below is there because each of these terms has one that is extremely common.
What it is
A cost segregation study breaks a purchase price into components and assigns each to its correct asset class. Carpet, cabinetry, specialty electrical, process plumbing and similar items can be personal property with short recovery periods; sitework, paving, fencing and landscaping can be land improvements with their own class; the structure remains 39-year or 27.5-year property.
Because more of the cost lands in short-life classes, deductions are pulled forward into the early years of ownership. The total deduction over the life of the asset does not change — the timing does.
What it tells you
How much of a building's cost can legitimately be recovered faster than the default schedule, based on an engineering analysis of what was actually bought.
What it does not tell you
Whether the acceleration is worth it. The study costs money, the benefit is the time value of an earlier deduction, and reclassified components are subject to their own recapture rules on sale.
The common misreading
Treating it as extra deductions rather than earlier ones. Pulling deductions forward increases the taxable gain later and can convert part of that gain into ordinary-income recapture on the personal-property components.
Where it sits in the sequence
Every commercial deal runs the same arithmetic in the same order. This measure is one line in it.
The list below is how a whole deal is worked out, from the rent on the schedule to the cash an owner keeps. Find the step this term belongs to and you can see what it has already counted and what it has not. What would mislead: quoting one line of this sequence as though it were the answer. Each step subtracts something real, and the ones after it subtract more.
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Rent roll
Contract rent, tenant by tenantStart from the leases, not from a summary. Each line has a start date, an expiry, an escalation schedule, options, and any free rent or unamortised concession still running. The rent roll is a legal document set, and the estoppel certificates are how a buyer confirms the tenants agree with it. -
Potential gross income
Contract rent + market rent on vacant space + other income + expense recoveriesWhat the property would produce fully leased, including parking, signage, storage, late fees and the reimbursements tenants owe for taxes, insurance and common-area costs. Recoveries are income and the matching expense is an expense — netting them hides the recovery ratio. -
Effective gross income
Potential gross income − vacancy − credit loss − concessionsDeduct what will not actually be collected: physical vacancy, tenants who do not pay, and concessions granted. Using an assumed market vacancy rather than the property's own history is one of the most common places a model becomes optimistic. -
Operating expenses
Taxes + insurance + utilities + repairs + management + admin + payrollThe cost of running the building for a year. Two lines deserve independent verification rather than acceptance: property taxes, which are frequently reassessed on a sale, and insurance, which is quoted to the buyer and not inherited from the seller. A market management fee belongs here even if the current owner charges none. -
Net operating income
Effective gross income − Operating expenses = NOIThe property's own income, before financing and before tax. This is the number that value, cap rate and every lender covenant are calculated from, which is exactly why it is the number most often presented flatteringly. -
Value and cap rate
Value = NOI ÷ Cap rate · Cap rate = NOI ÷ PriceOne equation used in both directions. Divide NOI by a cap rate to estimate value; divide NOI by a price to see what a deal is being priced at. Because value is derived from NOI, every dollar added to or removed from NOI moves the value by a multiple of itself. -
Capital items below the line
NOI − capital expenditure − tenant improvements − leasing commissionsExcluded from NOI by convention, but paid in cash. Roofs, parking lots, HVAC replacement, fitting out space for a new tenant and the commission that won the lease all come out of the same account. A reserve for them is the difference between an honest analysis and a brochure. -
Debt service
Cash flow before tax = NOI − annual debt service (− capital items)Interest and principal on the loan. This is where DSCR is tested, where the loan constant decides whether leverage is adding to or subtracting from cash flow, and where a covenant breach can divert income into a lender-controlled account before the owner sees it. -
After tax
Taxable income = NOI − interest − depreciation ± other adjustmentsCash flow and taxable income are different numbers. Depreciation is deducted though no cash left, principal repayment is cash out though it is not deductible, and the resulting loss may be suspended under the passive activity rules rather than used. At sale, recapture and gain settle the difference.
Primary sources
The authority on this, rather than an article about it.
In the Learn library: Commercial real estate.
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Visit Fundrise ↗Cost segregation — frequently asked
Is cost segregation aggressive?
Where do these numbers come from in a real deal?
This section is a structural reference, not investment, tax or legal advice, and nothing in it recommends buying, selling or financing any property. It contains no market quotes: no current cap rates, rents or prices, because those are negotiated privately and are not publicly quotable. Tax rules described here are general US federal mechanisms that change with legislation, and state and local rules differ. Verify anything that matters with an attorney, an accountant and an appraiser who know the specific property and jurisdiction.