An SNDA agreement — a Subordination, Non-Disturbance, and Attornment Agreement — is a three-party contract signed by a commercial tenant, the landlord, and the landlord’s mortgage lender that controls what happens to the lease if the landlord defaults and the lender forecloses. The tenant agrees its lease sits behind the mortgage in priority and that it will accept whoever takes title at foreclosure as the new landlord. In exchange, the lender promises not to terminate the lease or evict the tenant as long as the tenant stays current and in compliance. Without this document, a tenant whose lease is junior to the mortgage can be wiped out in foreclosure with no legal right to stay.
What the Three Letters Stand For
Each piece of the name does different work for a different party, and the three only make sense together.
Subordination
The tenant agrees that its lease is junior to the lender’s mortgage. If the property goes into foreclosure, the lender’s claim takes priority over the tenant’s right to occupy. This part benefits the lender. Even if the lease was signed before the mortgage was recorded, subordination reorders that priority so the lender’s security interest comes first.
Non-Disturbance
This is what the tenant gets back. The lender promises that if it forecloses, it will not terminate the lease or evict the tenant, provided the tenant is current on rent and not otherwise in default. Occupancy and operations continue under the existing lease terms. Agreeing to subordinate without securing non-disturbance is giving something for nothing.
Attornment
The tenant agrees to recognize whoever ends up owning the property after foreclosure as the new landlord. Rent and lease obligations continue, just paid to a different entity. For the lender, this preserves continuous rental income after a change in ownership and keeps the collateral attractive to buyers at a foreclosure sale.
What Happens in Foreclosure Without One
If the landlord defaults and the lender forecloses, any lease junior to the mortgage is extinguished. The tenant has no legal right to stay. The new owner can keep the tenant, renegotiate on less favorable terms, or require the tenant to leave.
For a commercial tenant, forced relocation is often serious financial harm. Businesses put real money into buildouts, signage, location-based marketing, and customer relationships tied to a specific address. Losing a lease because the landlord stopped paying its mortgage, through no fault of the tenant, can be devastating. The SNDA is the only document that contractually prevents that outcome.
Priority depends on timing. Real estate law generally follows a “first in time, first in right” rule, so a lease signed and recorded before the mortgage is senior by default, and foreclosure would not wipe it out. A lease signed after the mortgage is already junior. Many commercial leases also contain automatic subordination language that makes the lease junior to all mortgages, including future ones. In every one of those situations, non-disturbance protection has to come from an SNDA; nothing else supplies it.
When to Negotiate It
Timing drives leverage. The strongest position for a tenant is negotiating the SNDA before signing the lease. At that point, the landlord wants to close the deal and the lender wants a tenant whose rent supports the property’s debt-service coverage. Both sides have reasons to be flexible.
After the lease is signed, the dynamic shifts. Many commercial leases require the tenant to sign an SNDA within a set number of days of a lender request, or automatically subordinate the lease to future mortgages. Once you’ve agreed to that, the lender has little reason to negotiate, because you’re already contractually obligated to sign whatever it puts in front of you. The lender’s own form will naturally be written in the lender’s favor.
The practical move: insist the landlord deliver a signed SNDA from the lender as a condition of the lease, or at least negotiate the acceptable SNDA terms as an exhibit to the lease. Waiting until after the lease is executed to see the SNDA for the first time is the most common mistake tenants make.
Terms Worth Negotiating
Standard lender forms are drafted to protect the lender, and tenants who sign without pushing back often give up protections they could have kept. A few areas carry the most money.
Security Deposit
The standard lender position is that it has no obligation to return the tenant’s security deposit unless the lender actually received it from the landlord. Most landlords hold deposits in their own accounts and never transfer them to the lender. If the landlord defaults, goes bankrupt, or spends the money, the tenant may never see the deposit again.
Tenants can push back a few ways. One is to require the landlord to place the deposit in an escrow account held by the lender for the loan’s duration. Another is to reduce the deposit or replace it with a letter of credit, which takes the landlord’s ability to spend it off the table. At a minimum, understand that non-disturbance protection does not automatically guarantee the return of a cash security deposit.
Lender Cure Periods
Lenders routinely demand extra time to cure landlord defaults before the tenant can exercise remedies like lease termination or rent abatement. Some SNDAs require the tenant to send copies of all default notices to the lender and then give the lender its own separate cure period on top of the landlord’s. In aggressive versions, the lender’s cure period doesn’t start running until the lender completes foreclosure and takes possession. Accept notice to the lender, but cap any additional cure period at a specific number of days rather than leaving it open-ended or tied to the end of a foreclosure.
Prior Landlord Obligations
A standard lender-drafted SNDA says the lender will not be liable for defaults the previous landlord committed. If the old landlord owed you a tenant improvement allowance, failed to complete buildout work, or breached maintenance obligations, the lender’s position is that those problems stay with the old landlord. SNDAs also commonly say the lender won’t be responsible for defaults it cannot cure, such as obligations tied to the landlord’s bankruptcy. Push for the lender to honor outstanding tenant improvement allowances and buildout commitments, or at least allow the tenant to offset those costs against future rent.
Lease Amendment Restrictions
SNDAs frequently say no amendment to the lease is valid against the lender without the lender’s prior written consent. That protects the lender from discovering after foreclosure that the landlord and tenant quietly cut the rent, shortened the term, or expanded tenant rights.
The friction for tenants is that exercising a renewal option, expanding into adjacent space, or triggering an early termination right can all technically be documented as lease modifications. If every change needs lender consent, routine administration slows down. The standard carve-out is for amendments that document the exercise of rights already in the lease. The lender reviewed and approved the original lease, so exercising an option it already knew about shouldn’t require a second approval. Genuinely new amendments, like adding space not contemplated by the original lease or restructuring the rent, would still need consent.
Recognition of the Lease as Written
Make sure the SNDA states that the lender will honor the lease as written, including all exhibits, amendments, and side agreements, not just the base lease document. Confirm that casualty and insurance provisions, including rebuilding obligations and rent adjustments during repairs, survive foreclosure and bind the new owner.
How an SNDA Differs From an Estoppel Certificate
Lenders often request both documents at the same time, and tenants sometimes treat them as interchangeable. They aren’t.
An SNDA is forward-looking. It sets the rules for what happens to the lease if the property changes hands through foreclosure, and it creates new rights and obligations among three parties.
An estoppel certificate is backward-looking. It’s a snapshot of the lease’s current status, with the tenant confirming factual details: commencement date, current rent, expiration date, remaining renewal options, whether any defaults exist, what tenant improvement allowances remain unpaid, and similar items. It doesn’t create new rights; it prevents the tenant from later claiming the facts were different from what the certificate stated. A lender refinancing a commercial property will typically ask every significant tenant for both. Signing one doesn’t eliminate the need for the other.