What are an SNDA and an estoppel certificate, and why is your Denver landlord asking you to sign them?
An SNDA (subordination, non-disturbance, and attornment agreement) and an estoppel certificate are the two documents a landlord's lender or a prospective buyer asks an office tenant to sign, usually at lease signing, a refinance, or a building sale. They do opposite jobs. The SNDA decides whether you keep your space if the building gets foreclosed. The estoppel certificate is a sworn snapshot of your lease that you can be held to later, even if it is wrong. In Denver's 2026 office market, where downtown vacancy has crossed 38% and office loan distress runs well above the national average, the non-disturbance protection inside an SNDA is not boilerplate. It is the clause that keeps a lender's foreclosure from canceling your lease.
Most occupiers I work with have signed at least one of these without reading it. The request usually arrives mid-deal, framed as a formality, with a Friday deadline and a note that "the lender just needs this back." That framing is the problem. Both documents move legal risk onto you, and the moment you have leverage to fix them is short.
Here is what each one actually does, what it can cost you, and what to change before you sign.
The two documents do opposite jobs
An estoppel certificate looks backward and locks the present in place. You are certifying, in writing, the current state of your lease: the rent, the term, the security deposit, what is paid through, whether the landlord owes you anything, and whether either side is in default. A buyer or a lender relies on that statement to value the building. Once you sign, you are generally bound to it. If your estoppel says nothing is owed to you and the landlord actually owes you a tenant improvement allowance, you can lose that allowance. That is real money, often six figures on a full-floor deal.
An SNDA looks forward and governs what happens if the landlord fails. It has three moving parts:
- Subordination. You agree your lease sits behind the lender's mortgage in priority. Lenders want this so their loan outranks your leasehold.
- Non-disturbance. The lender agrees that if it forecloses, it will not evict you or cancel your lease, as long as you are not in default. This is the part that protects you.
- Attornment. You agree to treat the foreclosing lender, or whoever buys at the foreclosure sale, as your new landlord and keep paying rent.
Read those three together and the trade is obvious. Subordination and attornment are what the lender wants from you. Non-disturbance is the only piece that protects you. A subordination clause with no real non-disturbance is a one-way deal, and tenants sign it all the time.
Why this matters more in Denver right now
For a decade, an SNDA on a healthy building was close to a formality. Foreclosure was a remote risk. That is no longer the assumption you should bring to a Denver office lease.
Denver's downtown office vacancy reached 38.2% at the end of 2025, and the metro's office loan distress has been running well above the national average, with hundreds of millions of dollars in distressed balances concentrated in a handful of towers. National forecasts point to a wave of maturing commercial debt in 2026 as loans that lenders extended through the downturn finally come due against weaker rents.
Translate that into tenant terms. The building you are signing a seven-year lease in has a meaningfully higher chance of changing hands through a lender than it did five years ago. If that happens and your SNDA has a weak or missing non-disturbance clause, a new owner could try to terminate your lease, reset your terms, or ignore obligations the prior landlord owed you. The clause you skimmed becomes the difference between staying put and scrambling for space in a market that has moved.
This is the honest part most people will not tell you: the document that feels like the least important page in the stack is the one that protects you when the landlord is the party that fails.
What to fix in an SNDA before you sign
The leverage to negotiate an SNDA is highest before your lease is signed, when the landlord still needs your signature to close their own financing. Use it. Five things to push on:
- Make the non-disturbance real and unconditional. It should say that as long as you are not in default beyond your cure period, your lease continues on its existing terms after a foreclosure. Watch for carve-outs that let the new owner walk away from obligations.
- Bind the new owner to what you are owed. A lender's standard SNDA often says the new owner is not responsible for the prior landlord's defaults, prepaid rent, your security deposit, or an unfunded TI allowance. If your landlord owes you build-out money, that exclusion can erase it. Negotiate the new owner's recognition of those specific obligations.
- Protect your options and rights. Renewal options, expansion rights, a right of first refusal, and any purchase option should survive a foreclosure and bind the successor. Lenders frequently try to strip these.
- Keep your notice and cure rights. You want notice and a chance to cure before anyone treats you as in default, and ideally the right to receive copies of the landlord's default notices from the lender.
- Match the SNDA to your lease. The agreement should reference your actual lease terms, not generic ones. Inconsistencies get resolved against the tenant later.
What to check on an estoppel before you sign
An estoppel is shorter and feels harmless. It is not. You are signing a statement a third party will rely on and that can override your own understanding of vague lease terms. Before you return it, verify every line against your lease, your amendments, and any side letters:
- Rent, dates, and free rent. Confirm the current rent, the commencement and expiration dates, any rent steps, and any remaining abatement or free-rent period. If you have two months of free rent left, the estoppel should say so.
- What the landlord still owes you. This is where money leaks. If a TI allowance, a moving allowance, or any landlord work is unfunded or unfinished, write it in. Do not certify "no outstanding obligations" when there are some.
- Options and special rights. Renewal, expansion, contraction, ROFR, and purchase options should be listed. An estoppel that omits them can be read as a waiver.
- Defaults and disputes. If you have an open dispute, an offset claim, or a landlord default, disclose it. Signing "no defaults exist" can waive a claim you are actively working.
- Security deposit. Confirm the amount and form. A new owner inherits only what the estoppel documents.
The rule is simple. Never sign an estoppel that is inaccurate or that goes silent on something the landlord owes you. If the landlord's form is wrong, correct it before you sign rather than signing and arguing later. By then the document is the record.
One practical note. Most leases require you to return an estoppel within a set window, often ten to twenty days, and some leases let the landlord fill it in for you or treat its contents as true if you miss the deadline. So you cannot simply ignore the request. Move quickly, but move accurately.
These are legal documents with real consequences, so run both the SNDA and the estoppel past a commercial real estate attorney before you sign. The point here is to know what you are looking at and where the money and the protection live, so the review is fast and you are not negotiating blind.
If you are weighing the rest of your deal economics at the same time, the same discipline applies to which concessions to negotiate hardest and to auditing what you actually owe in operating expenses. The estoppel is where those numbers get frozen, so get them right before, not after.
Frequently asked questions
Do I have to sign an SNDA or an estoppel certificate?
Usually yes, because most commercial leases require a tenant to deliver both on request within a set deadline. That obligation is exactly why you negotiate the SNDA language up front, before the lease is signed, and why you correct an inaccurate estoppel rather than refusing it outright. Refusing without cause can put you in default of your own lease.
What is the real risk of signing an inaccurate estoppel certificate?
You can be held to what you certified, even if it contradicts your lease. The most common loss is an unfunded tenant improvement allowance: if the estoppel says nothing is owed to you, a new owner may not have to fund it. On a full-floor Denver office deal, that can be a six-figure mistake created by a single checkbox.
Does an SNDA protect me if my Denver landlord's building gets foreclosed?
Only to the extent of its non-disturbance clause. A strong SNDA keeps your lease in force on its existing terms after a foreclosure as long as you are not in default. A weak one lets the new owner cancel your lease or ignore what the prior landlord owed you, which is why the non-disturbance and successor-obligation language is worth negotiating, especially in the current Denver office market.
When do I have the most leverage to negotiate these documents?
Before your lease is signed. At that point the landlord needs your cooperation to close their financing or sale, so they have an incentive to push their lender for tenant-friendly SNDA terms. Once the lease is executed, you are largely signing the lender's standard form, and your room to negotiate shrinks.
Who pays for reviewing an SNDA or estoppel?
The tenant typically covers its own attorney's review, and it is money well spent given what these documents can cost if they are wrong. A tenant rep broker should flag the issues and coordinate the review so it is targeted and fast rather than an open-ended legal bill.
Both documents are routine to the lender and the landlord. They are not routine to you. The SNDA decides whether you survive a foreclosure with your lease intact, and the estoppel locks in what you are owed and what you can still claim. In a Denver market where landlord distress is a live risk rather than a theoretical one, the few hours you spend getting these right protect years of occupancy and real dollars.
If you have an SNDA or an estoppel certificate on your desk, or a Denver lease decision where the building's ownership feels uncertain, I am happy to run the language and the numbers with you before you sign. Schedule a conversation at calendly.com/mccririe.
About Brian McCririe
Brian McCririe is Executive Managing Director of SVN | Denver Commercial and National Council Chair for Occupier Services across the SVN network. After 25 years representing tenants and investors across global markets, he now focuses on the Denver Metro area helping companies navigate leases, acquisitions, and the gap between what landlords offer and what occupiers deserve. He leads one of the metro's top tenant rep practices and writes about the deals, decisions, and market shifts that matter to corporate real estate leaders.
