Assignment and subletting are two ways a commercial tenant transfers its interest in leased space to a third party, and the difference lies in what is transferred and who remains liable. An assignment transfers the tenant's entire remaining interest in the lease to a new party, who steps into the original tenant's position for the balance of the term. A sublease transfers only part of that interest, whether a portion of the space or a portion of the term, and creates a new landlord-tenant relationship between the original tenant and the subtenant while the original tenant remains directly liable to the landlord. In both cases the landlord's consent is usually required.
The practical consequence is liability. After an assignment, the original tenant may or may not be released depending on the lease language. After a sublease, the original tenant almost always remains fully liable to the landlord and simply becomes a middleman collecting rent from the subtenant. Understanding which structure a transaction uses, and what the lease permits, is fundamental to lease abstraction and to any deal involving occupied space.
Assignment Defined
In an assignment, the assignor transfers all of its rights and obligations under the lease to the assignee for the entire remaining term. The assignee becomes the tenant of record and deals directly with the landlord going forward. There is no remaining slice of the leasehold retained by the assignor; the whole interest passes.
The central question in any assignment is whether the original tenant is released from liability. This is governed by the assignment and subletting clause and the consent documentation.
Release status | Effect on original tenant |
Full release | Original tenant is off the hook entirely once the assignment closes |
No release | Original tenant remains secondarily liable if the assignee defaults |
Release with conditions | Release applies only if the assignee meets net-worth or other tests |
Landlords generally resist releasing the original tenant, because that tenant's creditworthiness was part of the original underwriting. A landlord that consents to an assignment but retains the original tenant's liability preserves a second party to pursue if the assignee fails. This is why "consent to assignment" and "release of liability" are separate points that must be captured separately during abstraction.
Subletting Defined
In a sublease, the original tenant, now the sublandlord, leases part or all of the premises to a subtenant for part or all of the remaining term. The original tenant keeps its direct relationship with the landlord and takes on a new relationship as landlord to the subtenant. The subtenant has no direct contractual relationship with the master landlord; its lease is with the original tenant.
This structure creates a layered arrangement. The master lease sits between the landlord and the original tenant. The sublease sits between the original tenant and the subtenant. If the master lease terminates, the sublease typically falls with it, because the subtenant's rights are derived from the original tenant's interest.
The master landlord leases to the original tenant under the master lease.
The original tenant subleases space to the subtenant under a separate sublease.
The subtenant pays rent to the original tenant, not to the master landlord.
The original tenant continues paying rent to the master landlord regardless of the subtenant's performance.
Because the original tenant remains fully liable under the master lease, a sublease shifts occupancy without shifting the primary obligation. If the subtenant stops paying, the original tenant still owes the master landlord.
Assignment vs Subletting Compared
The two structures differ across several dimensions that matter for underwriting and abstraction.
Feature | Assignment | Sublease |
Interest transferred | Entire remaining lease | Part of space or term |
New party's relationship | Directly with landlord | With original tenant only |
Original tenant liability | May be released or retained | Almost always retained |
Privity with landlord | Assignee has it | Subtenant does not |
Effect of master lease ending | N/A, assignee is the tenant | Sublease usually terminates too |
Typical use case | Business sale, permanent exit | Temporary excess space, partial floor |
A useful rule of thumb: if the tenant is leaving permanently and handing the whole lease to someone else, it is an assignment. If the tenant is keeping a foothold, offloading extra space, or covering a portion of the term while retaining its position, it is a sublease.
The Consent Standard
Most commercial leases prohibit assignment or subletting without the landlord's consent. The critical variable is the standard the landlord must apply. The difference between an absolute discretion standard and a reasonableness standard determines how much freedom the tenant actually has.
Consent standard | What it means |
Sole and absolute discretion | Landlord may refuse for any reason or no reason |
Not to be unreasonably withheld | Landlord must have a commercially reasonable basis to refuse |
Deemed consent | Consent is granted if the landlord fails to respond within a set period |
Permitted transfers | Certain transfers, such as to affiliates, need no consent |
The "not to be unreasonably withheld" standard is heavily negotiated. What counts as reasonable typically includes the proposed transferee's financial strength, its intended use, and its experience operating a comparable business. A landlord usually cannot withhold consent simply to extract a higher rent, though lease language sometimes lets it recapture the space or share in any profit instead.
Permitted transfer carve-outs are equally important. Many leases allow assignment to an affiliate, a successor by merger, or a purchaser of substantially all of the tenant's assets without consent. These carve-outs let corporate reorganizations proceed without landlord approval and are a standard abstraction field, because they define the transfers a tenant can execute unilaterally.
Profit Sharing and Recapture
When a tenant transfers space at a rent higher than it pays under the master lease, the question of who keeps the excess arises. Landlords frequently negotiate a right to some or all of that spread.
A profit-sharing provision requires the tenant to remit a percentage of any rent it collects from a subtenant or assignee above its own rent, often after deducting the tenant's transaction costs such as brokerage and improvement expenses. A recapture provision goes further, letting the landlord terminate the lease as to the affected space when the tenant proposes to transfer it, so the landlord can re-lease directly and capture the full upside.
These provisions materially affect the economics of a transfer. A tenant sitting on below-market space might expect to profit by subleasing at market, but a profit-sharing or recapture clause can redirect that gain to the landlord. Capturing whether these clauses exist, and their exact mechanics, is essential during abstraction because they change the value of the leasehold.
Why the Distinction Matters in Abstraction
For an acquirer or lender reviewing a rent roll, the assignment and subletting terms determine how easily tenants can change and who remains on the hook. A lease that permits assignment with a full release of the original tenant carries different credit risk than one that retains liability. A lease crowded with subleases means the parties actually occupying the building may differ from the tenants of record.
Several fields should be captured for every lease during review:
Whether assignment and subletting are permitted, and under what consent standard.
Whether the original tenant is released on assignment.
Any permitted transfer carve-outs for affiliates or successors.
Whether profit sharing or recapture rights apply.
Any notice and documentation requirements the tenant must satisfy.
These interact with other provisions. An exclusive use clause typically travels with an assignment, constraining the landlord's future leasing. An SNDA may govern how a subtenant's rights survive a foreclosure. Normalizing transfer rights across a portfolio into comparable fields is exactly the kind of work that structured abstraction and automated review handle well, because the terms are worded differently in every lease but need to be compared on a common basis. These belong in any thorough set of commercial lease abstract fields.
Frequently Asked Questions
What is the main difference between assignment and subletting? Assignment transfers the tenant's entire remaining interest in the lease to a new party who becomes the tenant of record. Subletting transfers only part of the space or term to a subtenant, while the original tenant keeps its direct relationship with the landlord and remains liable under the master lease.
Does the original tenant stay liable after an assignment? It depends on the lease and the consent documents. Landlords often retain the original tenant's liability even after consenting to an assignment, so the tenant remains secondarily responsible if the assignee defaults. A full release must be negotiated and captured separately from the consent to assign.
Can a landlord refuse consent to a transfer for any reason? Only if the lease grants sole and absolute discretion. Under the common "not to be unreasonably withheld" standard, the landlord must have a commercially reasonable basis, typically related to the transferee's finances, use, or experience. Many leases also exempt affiliate and successor transfers from the consent requirement entirely.
What happens to a sublease if the master lease is terminated? A sublease generally terminates with the master lease, because the subtenant's rights derive from the original tenant's interest. Some subtenants negotiate recognition agreements or an SNDA-style arrangement so their occupancy survives termination of the master lease, but absent such protection the sublease falls with it.
Conclusion
Assignment and subletting both move leased space to a third party, but they differ in what transfers and who stays liable: assignment passes the entire lease and may or may not release the original tenant, while subletting passes a portion and leaves the original tenant fully on the hook to the landlord. The consent standard, any release of liability, permitted transfer carve-outs, and profit-sharing or recapture rights all determine how freely space can change hands and who bears the risk. Capturing these terms precisely is fundamental to underwriting a rent roll and understanding who actually occupies and stands behind a lease.