The short answer
An SNDA (subordination, non-disturbance and attornment agreement) is a three-part agreement among a lender, a tenant and the landlord: the tenant's lease is made junior to the mortgage, the lender agrees not to disturb the tenant's occupancy after a foreclosure while the tenant is not in default, and the tenant agrees to recognize the foreclosure buyer as its landlord. It lets a lender lend against a leased building without wiping out the leases that give the building its value. For an exchange buyer financing a net-leased property, it is often a loan condition that needs the tenant's signature before day 180.
At a glance
| Subordination | The lease ranks behind the mortgage, existing or future |
|---|---|
| Non-disturbance | The lender will not end the lease on foreclosure if the tenant is not in default |
| Attornment | The tenant accepts the foreclosure buyer as landlord on the same lease |
| Federal lease model | The government's lease clause gives it 20 business days to sign subordination papers |
Each of the three words answers a different party's risk.
The federal government's standard lease clause, GSA Acquisition Manual 552.270-23, shows all three parts. The lease is subject and subordinate to recorded mortgages now or later placed on the premises, and the government will sign confirming instruments within 20 business days of a written demand. No subordination may adversely affect the government's rights while it is not in default, and the landlord must put that promise in the mortgage or a separate non-disturbance agreement.
On a foreclosure sale or deed in lieu, the government is deemed to have attorned to the purchaser, who assumes the landlord's obligations. Private leases vary, but lenders apply the same logic: the Fannie Mae Multifamily Guide requires each material commercial lease to be subordinate to the mortgage and to require the tenant to attorn to the lender, using its own SNDA form where needed.
A hypothetical: a net-leased replacement with a loan and a slow tenant.
Hypothetical figures: you sell a rental portfolio and contract to buy a single-tenant building for $4,000,000, using $2,000,000 of exchange equity and a $2,000,000 loan. The lender's commitment requires an SNDA and an estoppel certificate from the tenant before funding.
The tenant's lease obliges it to subordinate only if the lender grants non-disturbance, and its legal department takes four weeks to negotiate the form. If you identified this building on day 40 and signed the contract on day 60, that review lands well inside your 180 days, but only because you asked on day 60. Run your own timeline and numbers with your CPA and lender.
It bites in net lease purchases and in what a lease is worth after a default.
Section 1031(a)(3) ends the exchange 180 days after your sale, and a loan that waits on tenant paperwork can push your purchase against that date, which no lender delay extends; see lender delay and the 1031 deadline. Ask the seller at contract for any SNDAs the tenant signed for earlier loans and for the lease clause that governs them, and send the lender's form to the tenant the same week.
The document also decides value. Without non-disturbance, a foreclosing lender may be able to end a lease that sits behind its mortgage; without attornment, a tenant may treat a foreclosure as the end of its obligations. For single-tenant buildings, where one lease is most of the value, the single-tenant net lease property guide covers the other lease terms to check.
Related questions
Does an SNDA matter if I buy without a loan?
Less, because there is no new mortgage to subordinate to. An existing loan you assume, or a loan you add later, brings it back.
Is an SNDA the same as an estoppel certificate?
No. An estoppel confirms facts about the lease as of a date; an SNDA changes priorities and rights going forward. Lenders usually ask for both at once.
Do DST investors sign SNDAs?
No. The trust or its master tenant deals with the lender and tenants when the property is financed. The loan terms that matter to investors are in DST lender documents and carve-outs.
Sources
Checked against these publications on September 30, 2026. Rules and figures change; confirm the current version with your CPA or attorney before you act. This page is general information, not tax or legal advice.