Your commercial building is worth the net operating income a buyer can defend to their lender, divided by the capitalization rate the market will accept for that income, adjusted for whatever plan the buyer intends to run. That is the whole formula. Everything else in this guide is about how each piece of it gets built, argued over, and moved, because the gap between what owners believe their building earns and what buyers will underwrite is where value quietly changes hands.
I am a broker at Lee & Associates in Newport Beach and an ARGUS Enterprise Certified Professional. I value and sell office and industrial property across Orange County and the rest of Southern California, and I underwrite every assignment on the same platform institutional buyers and their lenders use. This guide covers the three valuation approaches and the only one that really matters, how cap rates actually work, how buyers rebuild your NOI, how value-add investors price your building, what a real broker opinion of value contains, what interest rates and debt do to all of it, and where the Southern California market sits right now with real numbers. If you want the condensed version of how I run the engagement itself, that lives on my investment sales and valuation process page. This is the long version, the one that explains why the process looks the way it does.
One framing before we start. Valuation is not a number, it is an argument. A good one anticipates every objection a buyer, an appraiser, and a lender will raise, and answers them before they are asked. A bad one is a cap rate applied to last year's income, and it dies in the first week of due diligence.
Appraisal theory gives you three ways to value real estate. The cost approach asks what it would take to buy the land and rebuild the improvements, less depreciation. The sales comparison approach looks at what similar properties recently sold for and adjusts. The income approach values the property as a stream of cash flows, either by capitalizing a single year of income or by discounting a multi-year projection back to present value.
For investment-grade commercial property, the income approach is the market. Buyers of office and industrial buildings are buying income, and they price it the way any income is priced: how much, how durable, how likely to grow, and what could interrupt it. The sales comparison approach still matters as a sanity check and a negotiating exhibit. When a 348,000 square foot Irvine industrial asset clears at roughly $307 per square foot, that print becomes part of every conversation in the submarket for the next two quarters. But comps inform the income approach; they do not replace it, because no two rent rolls carry the same risk.
The cost approach earns its keep in narrower situations: owner-user buildings where the buyer occupies rather than invests, special-purpose properties with no real comp set, insurance work, and new construction. In coastal Southern California it has one more use worth knowing: when land is scarce and replacement cost keeps climbing, the cost approach sets a floor under values that pure income math can miss. That floor is part of why Orange County industrial holds value through soft patches. Nobody is manufacturing more Irvine.
So when someone hands you a value, ask which approach produced it. If the answer is not "a defensible income analysis, checked against real comps," you have been handed an opinion, not a valuation.
A capitalization rate is one year of net operating income divided by price. A building producing $500,000 of NOI that trades at $10,000,000 traded at a 5 percent cap. That is all it is: an unlevered, single-year yield. It is also the inverse of a multiple, which is often the more honest way to think about it. A 5 percent cap means someone paid 20 times income. Say it that way and the question becomes obvious: what would make income worth 20 times, or 14, or 25?
Four things, mostly. First, interest rates and debt costs, because most buyers borrow, and the spread between what the building yields and what the debt costs determines whether leverage helps or hurts. Second, growth expectations. A below-market rent roll in a supply-constrained submarket justifies a lower cap rate on today's income because tomorrow's income is bigger. Third, durability of income: tenant credit, lease term, rollover concentration, and the cost of re-tenanting. A single-tenant building with three years of term is a very different animal from the same building with twelve. Fourth, liquidity, meaning how many buyers show up when the asset trades. Deep buyer pools compress cap rates all by themselves.
Two cautions. Asking cap rates in listings are marketing, not data; the only cap rates that matter are on closed sales with verified NOI. And a cap rate prices exactly one year. IRR, the return on the whole plan including rollover, capital, and exit, is what sophisticated buyers actually transact on. They talk in cap rates because it is a convenient shorthand. Owners who only know the shorthand negotiate at a disadvantage against buyers who know the whole sentence.
If the cap rate is the argument's grammar, net operating income is its subject, and here is the uncomfortable truth: no serious buyer accepts your NOI. They rebuild it from the rent roll up, and every adjustment they make moves your value at the full multiple. At a 5 percent cap, every dollar of NOI a buyer deletes costs you twenty dollars of price.
The rebuild follows a pattern. Rents get marked to market in both directions, so above-market leases get haircut at rollover and below-market ones become the buyer's upside rather than your value. A vacancy and credit-loss allowance goes in even if the building is full today, because underwriting prices the future, not the snapshot. A market management fee appears whether or not you self-manage, because the buyer will not work for free and neither will their lender's underwriter. Replacement reserves come out of income for roofs, HVAC, and parking. Recovery structures get audited against the actual leases, because a sloppy NNN reconciliation is found money for the buyer and lost value for you.
Then comes the California-specific adjustment owners forget most often: property taxes. Proposition 13 means your assessed value is frozen near your basis, but a sale triggers reassessment at the new price. The buyer underwrites the reassessed tax bill, not yours, and on long-held Southern California assets that single line can erase a surprising share of the NOI the seller advertised.
The practical lesson is simple. Underwrite your own building the way a buyer will, before you market it. Every weak line you find first is a line you can fix, explain, or price. Every one the buyer finds first becomes a retrade.
The most active buyers of multi-tenant office and industrial property in this market are not pricing your current income at all. They are pricing the income they believe they can create, minus the cost and risk of creating it. I wrote a full breakdown of this in how value-add buyers underwrite your building, but the mechanics belong in this guide too, because reading an offer correctly requires reading the buyer behind it.
The value-add underwrite is a story with numbers attached: buy at a basis, fix what suppresses income, exit at a value the improved income supports. The model makes explicit assumptions in four areas, leasing, capital, financing, and disposition, and then stress-tests whether returns survive when those assumptions get worse. What these buyers hunt is suppressed income with a curable cause: below-market rents from long, passive ownership; deferred maintenance and tired common areas that depress rents by more than the cost of the fix; operational slack in collections and recovery structures; and seller circumstances such as loan maturities, fund expirations, partnerships unwinding, and estates. Those circumstances affect price, not value, and buyers know the difference even when sellers do not.
Inside the model, four assumption groups drive most of the swing: market rent and the pace of getting to it, rollover downtime and renewal probability, capital cost and timing, and the exit cap rate. Small changes compound. Modest moves in renewal probability and downtime alone can swing value several percent before anyone even argues about the cap rate, which is why buyers negotiate your cap rate in public and your rollover assumptions in private.
Three implications for owners. Your rent roll is your valuation, so a leasing strategy that fixes rollover concentration before marketing is often the cheapest capital improvement available. Deferred maintenance is a leverage item, not a discount item, because buyers price the cure at their cost plus their margin, which always exceeds your cost. And a fragmented rent roll with a dozen small tenants rolling over two to three years reads as a rent-growth engine to a buyer, so make sure it is priced as one.
Owners have two formal ways to get a number. An appraisal is a certified document, commissioned for lenders, courts, estates, and partnership matters, and you pay for it. A broker opinion of value typically costs nothing, and it answers the question appraisals are not built to answer: what will the market actually pay, and how should you act on that? A real BOV includes verified sale and lease comps, current submarket conditions, a line-by-line read of your rent roll and rollover exposure, a supportable value range rather than a single flattering number, and a recommendation. If a BOV arrives as one page with a big number and no rent roll analysis, it is a business card, not an opinion.
The reason I build valuations in ARGUS Enterprise is not brand preference. ARGUS is the platform institutional buyers and their lenders use to model multi-tenant cash flows, because it handles what spreadsheets handle badly: dozens of leases with different terms, rollover timing, downtime, leasing costs, and recovery structures projected across a hold period. The certification exists because the software only outputs what the assumptions deserve. When your valuation is built on the same platform and the same assumption framework your eventual buyer will use, the number survives negotiation. When it is not, the buyer's model becomes the only model in the room, and their model was not built to flatter you.
My engagement runs in five steps: a no-cost broker opinion of value to establish whether the conversation is worth having; a full ARGUS underwrite when it is; scenario analysis across hold, sell, refinance, and restructure against your actual basis and debt; a written recommendation with the numbers behind it; and execution if the strategy calls for a transaction. On fees, the economics are simple. The BOV and the strategy work cost nothing. I am paid a commission only if a transaction closes, and the model decides whether one should, not the commission. Sometimes the model says sell. Often it says fix two leases and sell in eighteen months. Sometimes it says do nothing, and that answer still leaves you knowing exactly where you stand.
Nearly every buyer of commercial real estate uses debt, which means nearly every price is partly a lending decision. A buyer's maximum bid is constrained by three things their lender controls: the interest rate, the debt service coverage ratio the loan must clear, and the proceeds the lender will advance against the income. When rates rise, the same NOI supports less debt, the buyer's equity has to stretch further, and the price that pencils falls. This is why cap rates track interest rates over time, with a lag measured in quarters. Sellers anchor to yesterday's comps, buyers underwrite today's debt, and the bid-ask gap that results is precisely what a slow transaction market looks like.
The pivotal condition is what the market calls negative leverage: when debt costs more than the property yields on day one, borrowing reduces the buyer's return instead of amplifying it. Buyers will accept it only when income growth is credible enough to outrun it, which is why supply-constrained industrial with below-market rents keeps trading through rate cycles while commodity assets with flat income sit.
Debt also shapes value from the seller's side, and this is the part owners underestimate. Loan maturity data is commercially available, and disciplined buyers track it systematically. If your debt matures inside the next 24 months, assume every serious buyer knows, has a view on your refinancing options, and is pricing your timeline into their offer. My own sourcing systems monitor maturities across Southern California for exactly this reason, on behalf of both sides of that trade. The strategic point: a maturity is not a reason to panic-sell, it is a reason to run the hold, sell, refinance, and restructure math early, while you still have all four options. Owners who start that analysis two years out choose their outcome. Owners who start it two quarters out have it chosen for them.
Valuation happens in a market, so here is the market, with real numbers. In Orange County industrial, per Kidder Mathews' Q2 2026 research, direct vacancy reached 6.0 percent, up from 5.8 percent the prior quarter, with total availability at 9.2 percent. Average asking rents sit at $1.45 per square foot per month NNN, down 5.2 percent year over year. Quarterly net absorption was negative 331,000 square feet, and year-to-date leasing of roughly 5.6 million square feet is running about half of last year's pace. That is a soft tape. But the number that matters most for valuation is the trend underneath it: year-to-date absorption of negative 174,000 square feet is a dramatic improvement from negative 1.4 million square feet in 2025, and the construction pipeline is thin, with roughly 287,000 square feet delivered in the quarter. Slowing bleed plus scarce new supply is what the early stage of a bottom looks like, and I unpacked the full picture in the Orange County industrial market guide.
Spread matters as much as average. Submarket asking rents range from about $1.09 in Costa Mesa to over $2.00 in the south county coastal cities, and my zip-level tracking shows why the income side holds up: industrial vacancy runs around 4 percent in Costa Mesa, Lake Forest, and El Segundo, and about 5 percent in the Irvine Spectrum. Office is a different story and a different valuation problem. Newport Beach office vacancy sits near 11 percent, Irvine's core near 13 to 14 percent, Century City at 18 percent, and downtown San Diego at 22 percent. Identical cap rate math produces wildly different answers across those markets, which is the whole case for submarket-level underwriting.
One more Southern California peculiarity: the buyers and owners live somewhere specific. Newport Coast households average $204,291 in income and Rancho Santa Fe $250,000, and a disproportionate share of the region's private ownership sits in those coastal corridors. I track 149 zip codes of this wealth, business-density, and vacancy data across five regions; the picture is on my interactive market maps and the coverage page.
Get a real valuation before any decision that depends on the number, and specifically when any of these triggers appear: your loan matures inside 24 months; you are weighing a 1031 exchange and need to know what equity you are actually playing with; a partnership, estate, or fund-life event is approaching; a concentration of leases rolls in the next two to three years; or an unsolicited offer lands and you have no independent basis to judge it. Since a broker opinion of value costs nothing, the honest answer is also the simple one: annually, the way you would review any other major asset, and immediately when a trigger fires.
The mistakes I see repeatedly are all versions of the same error, letting someone else's number stand in for your own underwriting. Pricing off a neighbor's sale without knowing its rent roll. Believing asking cap rates instead of closed ones. Advertising an NOI that ignores reassessed taxes, management, and reserves, then acting surprised by the retrade. Treating deferred maintenance as a modest discount when buyers price it as leverage. Marketing a building with a rollover problem the buyer discovers before you do. And waiting for a perfect market instead of preparing for a real one, when the owners who fixed their rent rolls during the soft quarters are the ones who meet the recovery from strength.
Here is the offer, plainly. Whether you own industrial in the airport corridor, office in Newport Center, or flex in Sorrento Valley, I will run the broker opinion of value at no cost, show you the model, and tell you what I would do if it were my building, including when the answer is do not sell. If you want a number you can defend, start the conversation here.
Almost entirely through the income approach: net operating income divided by a market capitalization rate, checked against recent comparable sales. Sophisticated buyers go further and model lease-by-lease cash flows over a full hold period, so the real value is the price their projected returns support.
A cap rate is one year of net operating income divided by price, an unlevered yield. It moves with interest rates and debt costs, expectations for rent growth, the perceived durability of the income (credit, lease term, rollover), and how liquid the asset class is. It is a shorthand for risk, not a law of physics.
An appraisal is a certified document you pay for, built for lenders and legal purposes. A broker opinion of value typically costs nothing and answers a different question: what will the market actually pay, based on comps, submarket conditions, and the same underwriting buyers use. A good BOV is built in ARGUS on buyer assumptions.
Most buyers use debt, so their maximum price is set by borrowing costs, debt service coverage, and lender proceeds. When debt costs more than the property yields, leverage works against the buyer and prices adjust downward. Cap rates follow interest rates with a lag, which is why rate moves show up in values over quarters, not days.
They price the income they believe they can create, minus the cost and risk of creating it. The model makes explicit assumptions in four areas, leasing, capital, financing, and disposition, and backs into the price their required returns support. Your asking price is an input to negotiation, not to their model.
Before any decision that depends on the number: a loan maturing inside 24 months, a 1031 exchange, a partnership or estate event, heavy lease rollover ahead, or an unsolicited offer. A broker opinion of value usually costs nothing, so the practical answer is annually, and immediately when any of those triggers appear.
New articles publish here automatically every week from my market monitoring system.
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Tell me what you're working on: a lease coming up, a building to buy or sell, or a market question you want a straight answer to. I'll respond within one business day.