Cap Rates: The One Number That Prices Every Building
Every property on earth, from a duplex to a data center campus, is priced by the same fraction: income over value. Learn to read cap rates and the entire real estate market becomes one legible spreadsheet.
The Fraction That Runs the Industry
Ask what any commercial building is worth and the industry answers with one fraction. The capitalization rate, cap rate, is a property\'s net operating income, NOI, the rent collected minus operating expenses, before any mortgage costs, divided by its price. A building producing 500,000 dollars of NOI selling for 10 million trades at a 5 percent cap rate, and the fraction runs both directions, agree on a market cap rate and any income stream converts instantly to a value, 500,000 of NOI at a 6 cap is worth 8.33 million. It is the real estate sibling of the earnings yield on stocks and the coupon on bonds, one number carrying price, risk, and expectation simultaneously, which is why every property conversation among professionals begins with it and why this article sits first in this site\'s real estate toolkit.
Reading the Number
The cardinal rule inverts intuition, low cap rates mean expensive, high cap rates mean cheap, because the rate is the yield investors accept. From there, cap rates read as a risk and growth map. Safe, growing income commands a low rate, the apartment and data center assets this site profiles trade around 5 to 6 percent, their income floored by housing shortages and hyperscaler leases. Risky or shrinking income demands a high one, commodity office after the reset our coverage describes trades at cap rates in the high single digits and beyond, when it trades at all. Within one property type, the same gradient prices location and quality, a trophy tower in a prime district versus the same income in a struggling suburb can differ by hundreds of basis points, hundredths of a percent. And embedded in every low cap rate is a growth forecast, buyers accepting a 4.5 percent yield are betting the NOI grows into the price, which is the exact logic, and the exact failure mode, of a high P/E stock.
The arithmetic is violently leveraged, at a 5 cap, every 25 basis point move in the market cap rate swings the building\'s value by roughly 5 percent, with the income unchanged. Most of real estate\'s boom and bust is not rents moving. It is the denominator.
The Spread That Sets the Cycle
Where do market cap rates come from, from the bond market, with a lag and an attitude. Investors price property as a spread over the risk free 10 year Treasury this site\'s yield curve article explains, historically 200 to 300 basis points of extra yield for real estate\'s illiquidity and risk. The 2020s ran the natural experiment, when Treasuries yielded under 1 percent, 4 cap apartments looked generous and prices boomed, when the 10 year jumped toward 4.5 percent through the hiking cycle our Looking Back series covers, the spread math demanded higher cap rates, and values fell 20 to 40 percent depending on property type, worst where income also broke. The 2026 state of play, with the 10 year near 4.6, cap rates have plateaued at their reset levels, transactions have restarted as sellers accepted the new arithmetic, and forecasters expect modest compression only as and if rates ease, the entire cycle legible from one spread.
Using It Like a Professional
Three habits complete the tool. Interrogate the NOI before trusting the rate, a broker\'s pro forma cap rate built on projected rents and understated expenses is marketing, the number computed on actual trailing income is analysis, and the gap between them is where bad deals hide. Distinguish going in cap rates from exit assumptions, every underwriting model, including the LBO style deals our finance coverage explains, embeds a guess about the cap rate at future sale, and assuming exit rates lower than entry, betting on the market getting more expensive, is the most common way real estate models lie politely. And use cap rates comparatively, the number is most powerful as a cross section, if two similar buildings trade 150 basis points apart, one is mispriced or one has a problem, and finding out which is the actual job of real estate analysis.
The Bottom Line
The cap rate is real estate\'s universal price, income over value, low means expensive and confident, high means cheap and worried, set as a spread over Treasuries and moving values by percentage points per quarter point. Learn to compute it on real income, read it against the bond market, and treat every embedded exit assumption with suspicion, and you can price your way through the rest of this site\'s real estate coverage, and any building you will ever walk past, with one fraction.