Most investors look at a cap rate and ask whether it's a good number. A 6.5 on a strip center. A 5 on a single-tenant net lease. A 7.5 on a multi-tenant office building in a secondary market. The question is always some version of: is that the right number for that kind of asset? It's the wrong question.
Not because cap rates don't matter — they're how every commercial deal gets priced — but because the cap rate itself is just a summary. It's an output. The thing actually being priced is something most buyers never name out loud, and once you start thinking about it directly, every cap rate you've ever looked at starts to make more sense.
What's actually being priced
A cap rate is the market's bet on the durability of an income stream. Not the income itself — the durability of it.
For anyone newer to this: cap rate is just net operating income divided by purchase price. A 6.5 cap on $1M of NOI prices the asset at about $15.4M. Lower cap rate, higher price for the same dollar of income. Higher cap rate, lower price.
That math is simple. What it represents isn't.
Real estate value is a derivative of the leases you sign. The building is the wrapper. The income is the substance. And the income is only as valuable as the probability it actually shows up in your account every month for the full term of the lease — and the term after that, and the term after that.
That probability is what I think of as durability of income. It's the joint likelihood across four things: the tenant's credit and operating health, the lease term itself, the re-leasability of the box if the tenant walks, and how the tenant fits into the surrounding ecosystem. None of those four are the same as "credit quality." Credit is one input. A BBB-rated tenant in a dying corridor with a single-purpose box has worse durability than a well-capitalized local operator anchoring a thriving mix. The market knows this even when buyers don't.
When you start looking at deals through the durability lens, the cap rate spread between any two assets starts telling you something specific: the market's collective view on how confident it is that each income stream will hold.
What the spectrum tells you
Take the two ends.
A single-tenant Wawa on a corporate-guaranteed twenty-year absolute net lease trades at a cap rate in the high 4s, sometimes lower. The market is paying north of $20 for every dollar of NOI. Why would anyone pay that much? Because the durability is unusually high. Wawa corporate is well-capitalized, the lease is long, the locations are picked obsessively for traffic and demographics, and even if Wawa eventually leaves the box, the dirt is usually re-leasable to another credit user. Every layer of durability — credit, term, location, re-leasability — is stacked. The market prices the certainty.
Now take a multi-tenant strip center anchored by Office Depot or Bed Bath, where the anchor is on a five-year extension and the broader retail concept is in slow decline. That deal might trade at an 8 cap or higher. Same dollar of NOI, half the price. Why? Because the market thinks there's a real chance the anchor goes dark inside the term, and when it does, your in-line tenants either renegotiate down or leave under co-tenancy clauses, and the box itself is hard to re-tenant at the same rent. The durability is poor. The cap rate compensates.
Same NOI today. Different price. Not because the income is different — because the market doesn't believe one of those income streams will hold.
This is the part most investors miss when they ask whether a cap rate is "good." A high cap rate isn't a deal. It's a warning. The market is telling you what it thinks of the durability, and if anyone is going to buy that asset, they better have a thesis for why the market is wrong — or for what they're going to do about it after close.
Time isn't flat
Here's the part that trips up even sophisticated buyers. Durability isn't constant across the term of a lease.
The first 24 months of any new lease are the riskiest. Tenant improvement allowances are unrecovered. Leasing commissions are unamortized. The tenant's cash flow is most fragile because they're still ramping. If a tenant signs a ten-year deal and walks in year two, you don't have a ten-year income stream — you have a two-year stub, an empty box, and a hole in the pro forma roughly the size of all the capital that went in to land them.
A lease that has survived its first three years is materially more durable than the same lease at signing, even though the document hasn't changed. The tenant has demonstrated it can operate in the space at rent. The customer base has formed. The cash flow ramp is behind them. Year-three NOI is worth more than year-one NOI, and not just because of discounting.
This is why I'm cautious about deals priced off a freshly signed headline lease term. Ten years on paper doesn't mean ten years of income. The shape of the risk over time matters, and it's front-loaded. When I'm underwriting a building on the back of a brand-new lease, I'm paying for income that hasn't been stress-tested yet — and I treat that NOI as more provisional than the rent roll suggests.
Where operators actually earn their keep
Credit tenants and dark-anchor problems are the easy cases. The market prices both reasonably efficiently. The hard cases — the ones where there's actual money to be made, and lost — are mom-and-pop tenants in multi-tenant centers.
You can't underwrite a local tenant by pulling a credit report. There usually isn't one worth pulling. So you have to do the work credit agencies don't do.
When I underwrite a local retailer, I look at five things.
First, access to capital. How thin is their margin for error? What happens to them in a slow quarter, or a six-week construction disruption on the block? Have they raised money from anyone, do they have a working line of credit, do they have personal liquidity behind the lease?
Second, landlord references. Not the one they list — the ones they don't list. The previous landlord will tell you in five minutes whether this tenant pays on time, whether they take care of the space, whether they call about real problems or invent them.
Third, an actual business plan that survives basic scrutiny. Not a deck. A plan that explains who their customer is, what they charge, what their unit economics look like, and what they need to do in week one and month six and year two.
Fourth, fit with the surrounding demographic. Does what they're providing match what the people living within three miles actually want and can afford? You'd be surprised how many leases get signed where this question was never seriously asked.
Fifth, and most underrated, complementarity. Does this tenant feed off the foot traffic of the existing mix, and does the existing mix benefit from them being there?
None of these inputs sit in a credit report. All of them sit in the income stream the lease either does or doesn't produce. The work is figuring it out before you sign — not after a tenant goes dark.
The ecosystem compounds
Durability isn't measured per lease. It compounds across a center.
The right tenant mix raises the renewal probability of every neighboring lease. It raises the rent you can ask at turnover. It shortens vacancy, because the corridor itself becomes more attractive to prospective tenants. It also reduces carry costs across the building, because foot traffic goes up and cap-ex requests go down when tenants are doing well.
The opposite compounds too. A vacancy in one suite drags the renewal probability of every neighbor. A struggling tenant who can't keep their storefront clean signals to the rest of the block that this isn't a serious operating environment. A bad mix doesn't just cost you one rent. It slowly erodes the durability of every other rent in the building.
Each lease is in conversation with every other lease. The operator's job is to make sure those conversations are productive ones.
Durability is manufactured, not just measured
Most of what I've described so far is durability as something you assess before you buy. That's the investor-side view. The operator-side view is different — and more interesting.
Durability isn't fixed. It's something you actively build into the asset after close. Disciplined operators raise the durability of their income stream every quarter through specific decisions. Who they let into the building. How they structure leases — personal guarantees, performance step-ups, tighter co-tenancy clauses. How much capital they keep in reserve to bridge tenant transitions. How aggressively they maintain the physical asset so that vacancies refill quickly when they happen.
This is the part that doesn't show up in any pro forma. It's also the part that explains why two operators can buy the same asset at the same cap rate and end up five years later with materially different cash flows. They're not just collecting rent. One of them is making the income stream more durable every year. The other is letting it drift.
This shaped how I think about the work, in part because of my time at WeWork. WeWork made plenty of mistakes, but one thing they understood at the operating level was that the durability of any given location's income was a function of decisions you made every day.
The mix of members, the quality of the space, the response time on issues, the curation of the community. Those decisions either compounded into stronger income or eroded into weaker income. Real estate is the same. Most investors think they're buying assets. They're actually inheriting decisions, and signing up to make new ones.
What the math actually says
Here's the test. Pull up two deals. Both are doing $1M of NOI. One trades at a 5 cap. One trades at a 10 cap.
The 5 cap is priced at $20M. The 10 cap is priced at $10M. Same dollar of income today. Twice the price for one of them.
Nobody is paying $20M instead of $10M because they enjoy spending more money. They're paying it because they believe — and the market believes — that the dollar of NOI on the 5 cap is going to keep showing up, year after year, with very high probability. They're paying for certainty. The 10 cap buyer is being compensated, in price, for the chance that the dollar doesn't show up.
That's all a cap rate ever is. A price the market sets on certainty. The number itself doesn't tell you whether a deal is good or bad. It tells you what the market thinks of the durability. The work is figuring out whether the market is right, whether it's wrong, or whether you can change the answer after close.
What the cap rate doesn't tell you
Cap rates describe the present. Durability determines the future.
Every cap rate you've ever looked at is a snapshot — the market's view, today, of an income stream that hasn't happened yet. The buyers who do well in this business are the ones who develop their own view of that durability and then act on the gap between their view and the market's. Sometimes that means paying up for an asset the market is undervaluing because it doesn't see the operating upside. Sometimes it means walking away from a deal at a cap rate that looks attractive on paper, because you know what the market is telling you and you don't have a thesis for why it's wrong.
The cap rate is the market's guess. The income is the verdict. The work is everything in between.