Due Diligence Guide for Commercial Real Estate Buyers
Deals can start to fail in the weeks between contract and closing, when the pressure to get to the finish line starts to outweigh the discipline to ask the right questions.
Due diligence in commercial real estate is the part of the process where you either confirm what you think you're buying or discover that the story doesn't hold up under scrutiny. The difference between an investor who builds a strong portfolio and one who spends years unwinding bad decisions usually comes down to how disciplined they were during this phase.
These are the six areas I examine on every acquisition, and the specific things I'm looking for inside each one.
1. Tenant Financials: What Tax Returns Tell You
Tenants and brokers can tell you business is solid, but verbal assurances aren't something you can underwrite.
I recommend requesting three years of tax returns to see the full financial picture. What's reported to the IRS tends to reveal the truth about a business in ways that a conversation never will.
I’m always looking for profitability, but the biggest thing that I need to see is a consistent pattern. One strong year followed by two declining ones is a red flag regardless of how the tenant explains it. Wild revenue swings can indicate a cyclical business or one facing structural headwinds that the tenant hasn't volunteered.
Three years of consistent returns with healthy margins tells you the tenant is stable. A tenant who hesitates to provide them, or whose returns show thin margins and declining performance could be a major risk.
2. Historical Lease Compliance: Talk to the Current Landlord Directly
One of the most reliable pieces of due diligence you can do costs nothing but a phone call.
Contact the current landlord directly and ask about payment history over the last three to five years. Tenants won't volunteer information about late payments or maintenance disputes, and brokers representing the deal have no incentive to surface them either.
Ask them:
Has the tenant paid on time consistently? And if there were late payments, what was the reason?
Are there any pending disputes? Maintenance issues, lease violations, anything contentious?
What's the relationship like? Is the landlord happy? Would they renew the tenant if they could or are they ready for them to leave?
Have there ever been collection issues or notices? Even if resolved, you want to know.
The answers to these questions will tell you more about what to expect from this tenant than anything in the offering memorandum.
3. Market Rent Validation: Know If You're Buying Upside or Overpaying
The gap between in-place rent and market rent is one of the most common ways buyers get hurt on a deal without realizing it until after closing.
For example, a property generating $400,000 a year from a tenant paying $8/SF on 50,000 SF seems like reasonable income, until you start talking to brokers in the market and learn that comparable space is leasing at $12/SF. At that point, you're holding a below-market lease that a lender may not underwrite at face value and a tenant who almost certainly won't accept a 50% rent increase at renewal.
Validating market rent before you close means pulling comparable leases, talking to brokers who are active in that submarket, and understanding what similar properties are actually trading at right now.
If you're buying a property with below-market tenants, ask yourself:
Can you refinance based on what's in place, or are lenders going to discount the market?
When does the lease renew, and how much runway does the tenant have left?
How easy is it to lease comparable space in this market if the tenant walks?
Knowing the answers to these questions can be the difference between generating income and buying a problem that compounds every year.
4. Exit Strategy Clarity: Know How You Get Out Before You Get In
Every acquisition decision should start with the exit. Before you close, you need to be able to clearly articulate how you get out of this asset under both ideal and adverse conditions.
Can you refinance if the market turns? Is the tenant creditworthy enough that a lender will underwrite based on their lease? If the market goes sideways, is this an asset you can sell, or does a weak tenant profile make it difficult to move? If you can't specifically answer those questions before closing, you're not ready to close.
The difference between an acquisition with a strong tenant and a weak tenant, is that the risk profile is fundamentally different and needs to be understood going in.
A bankable tenant gives you options: refinance, pull equity, hold long-term, or sell to a cap-rate buyer in five to seven years. But a month-to-month tenant in a softening market leaves you carrying debt with no income and no clear timeline for resolution.
That second scenario can still work, but only if you've stress-tested it honestly and you have a realistic plan if things don't go the way you modeled them.
5. Landlord Relationship History: You're Buying the Tenant as Much as the Building
Acquiring a property with existing tenants means inheriting the relationships that come with it.
A tenant with a history of fighting over maintenance, disputing lease terms, and creating friction with previous landlords is going to bring that same behavior to their relationship with you.
I would contact as many previous landlords as possible and come prepared with the following questions:
How did the tenant handle maintenance?
Were they reasonable about what fell within their responsibility, or did they dispute everything?
Were there lease disagreements over rent, use of space, parking, or yard access?
And perhaps most telling: would the landlord work with them again, and how quickly do they answer that question?
A landlord who says "absolutely" without hesitation is a very different signal than one who hesitates and says "sure, if the rent was right." A tenant who is operationally difficult but financially strong is a manageable situation, and it’s crucial to understand what you’re getting yourself into.
6. Zoning and Use Verification
Zoning compliance is one of the most overlooked items in commercial due diligence because it typically doesn’t surface until after you own the problem.
A tenant can operate in a space for years without anyone raising a red flag, and as a buyer you'd have no reason to question it. But long-standing use and permitted use are two entirely different things, and municipalities don't grandfather in violations just because they've gone unaddressed. When the city does get involved through a complaint, an inspection, or a routine review, you're the one holding the deed.
Before closing, verify directly with the local zoning office that the tenant's current use is actually permitted under the property's zoning classification. If they're operating under a variance or conditional use permit, confirm it's still valid, when it was granted, and whether it carries an expiration date. It's also worth checking the municipality's code enforcement database for any open complaints or violations tied to the address. Many cities make this available online and it only takes a few minutes to review.
A single phone call to the zoning office before closing can tell you everything you need to know. Making that same call after you own the property is a much more expensive conversation.
The discipline is what separates you
Due diligence can be uncomfortable because it's the part of the process where you're actively looking for red flags on a property you've already decided you want. The hard questions that aren’t asked up front end up turning into costly problems down the line. This causes tension for some new buyers, but showing discipline during this stage will save you money and headaches in the long run.
Matthew Antonis
Matthew Antonis is a leading figure in the DMV market, recognized for his specialized expertise in Industrial Property and unwavering dedication to client success. His career is defined by high-impact transactions and a data-driven approach that consistently sets new benchmarks in the region.
Matthew made his mark immediately with a monumental debut transaction: securing 161,792 square feet across 11.73 acres, encompassing 14 buildings for $15.2 million. This early success set the tone for a career characterized by lucrative deals and repeat clientele who trust his deep knowledge of the industrial sector.
