In legal and financial documents, the correct spelling is assignor, not “assigner.” An assignor is the party who holds a right or interest under a contract and transfers it to another party, called the assignee. Both spellings appear in general dictionaries, and both mean the same thing, but legal practice has settled firmly on the -or form. So when you are choosing between assigner or assignor for a deed, a contract, or a court filing, use assignor.
Why Legal Writing Prefers Assignor
Merriam-Webster actually lists “assigner” as the base form and “assignor” as a variant. In casual English, either is defensible. Legal writing follows its own convention: the -or suffix marks the person performing a legal act, and the -ee suffix marks the recipient. Grantor and grantee. Mortgagor and mortgagee. Lessor and lessee. Obligor and obligee. Assignor and assignee fit the same pattern, which is why the Uniform Commercial Code, the Restatement of Contracts, and the standard forms used in every U.S. jurisdiction use “assignor” exclusively.
Using “assigner” in a contract will not void it, but to a lawyer or judge reading the document it will look like a typo. There is no practical reason to reach for it when the legal form is just as easy to type.
What an Assignor Does
An assignor transfers a right, benefit, or interest they hold under a contract to someone else. The Restatement (Second) of Contracts describes assignment as a manifestation of the assignor’s intention to transfer a right; the effect is that the assignor’s right to performance is extinguished, and the assignee holds it instead. Once you assign, you no longer have what you assigned. The assignee steps into your position.
Common examples:
- Transferring the right to collect payments under a promissory note.
- Handing a lease over to a new tenant.
- Reassigning intellectual property royalties.
- Selling accounts receivable to a factoring company.
The assignor typically signs a written assignment document that identifies the parties and describes the right being transferred. Oral assignments can be valid for smaller transactions, but the UCC historically required a writing for assignments of certain personal property interests exceeding $5,000, and the statute of frauds in most states requires a writing when the transfer involves interests in land or goods above a threshold amount.
Assignment Is Not the Same as Delegation
People often blur these two, and the difference has real consequences.
Assignment transfers rights — the ability to receive something, like a payment or a performance. Delegation transfers duties — the obligation to do something, like deliver goods or complete a service.
Under the UCC, when someone assigns “the contract” or “all my rights under the contract,” that language is read as transferring rights and simultaneously delegating the assignor’s duties, unless the context suggests otherwise. The assignee’s acceptance of the delegation counts as a promise to perform those duties, enforceable by both the assignor and the other original party.
Here is the part that catches people out. Delegation does not eliminate the original party’s responsibility. The UCC states plainly that no delegation of performance relieves the delegating party of any duty to perform or any liability for breach.1Legal Information Institute. UCC 2-210 Delegation of Performance; Assignment of Rights If you delegate your obligation and your delegate fails, you are still on the hook.
The Assignee and Why Notice Matters
The assignee is the receiving party — the one who picks up the rights the assignor gave up. After a valid assignment, the assignee can enforce those rights directly against the obligor (the party who owes performance under the original contract).
Notice is not technically required for the assignment to be valid, but it matters enormously in practice. An obligor who performs for the original assignor without knowing about the assignment is discharged from that obligation. So if a debtor keeps sending payments to the assignor because no one told them the right had been transferred, the assignee cannot recover those payments from the debtor. The assignee’s only remedy is against the assignor, who collected money they were no longer entitled to receive.2Legal Information Institute. UCC 9-406 Discharge of Account Debtor; Notification of Assignment
Rights That Cannot Be Assigned
Not every contractual right is transferable. Courts and statutes recognize several categories where assignment is restricted or prohibited.
- Material change in the obligor’s burden. An assignment is unenforceable if it would substantially change what the other party has to do, increase their risk, or reduce their chance of receiving return performance. The UCC codifies this for sales contracts.1Legal Information Institute. UCC 2-210 Delegation of Performance; Assignment of Rights
- Personal trust or skill. Contracts that depend on a specific person’s judgment, expertise, or character — an attorney-client relationship, a commission for a particular artist — generally cannot be assigned, because the obligor bargained for that specific person.
- Personal injury claims. Most states prohibit assignment of personal injury tort claims on public policy grounds, to discourage speculative litigation by third parties who buy up potential lawsuits.
- Employment duties. Workers generally cannot assign their employment obligations to someone else, since the employer hired a specific person.
- Government claims. Federal law tightly restricts assignments of claims against the United States. An assignment is only valid after the claim has been allowed, the amount decided, and a payment warrant issued; the assignment must be in writing, attested by two witnesses, and acknowledged before a certifying official.3Office of the Law Revision Counsel. 31 USC 3727 – Assignments of Claims
Anti-Assignment Clauses
Many commercial contracts include a clause prohibiting assignment without the other party’s consent. These clauses are generally enforceable when they restrict assignment of services or duties. The UCC carves out a significant exception, though: contract terms that prohibit the assignment of accounts, payment rights, chattel paper, or promissory notes are largely ineffective under Article 9.2Legal Information Institute. UCC 9-406 Discharge of Account Debtor; Notification of Assignment The same principle extends to general intangibles and health-care-insurance receivables.4Legal Information Institute. UCC 9-408 Restrictions on Assignment of Promissory Notes
The reason is commercial: businesses need to be able to use their receivables as collateral for financing, and letting individual contracts block that would undermine secured lending. So even if a contract says “no assignment,” the right to receive payment under it can usually still be assigned as loan collateral. A prohibition on assigning “the contract” as a whole is typically read as barring only the delegation of duties, not the transfer of rights.1Legal Information Institute. UCC 2-210 Delegation of Performance; Assignment of Rights
Is the Assignor Off the Hook After Assigning?
Usually not. Assigning rights, and even delegating duties, does not by itself release the assignor from the original contract. The assignor generally remains liable for performance obligations unless the other contracting party agrees to a release. In a lease assignment, the original tenant can still be pursued for rent if the new tenant defaults, unless the landlord consented to a full release when the assignment happened.
The mechanism for a clean exit is a novation. A novation replaces the original contract with a new one. All three parties have to agree: the incoming party accepts full liability, the other original party accepts the substitution, and the old contract is extinguished. Only then is the original party truly released.
If you are assigning a contract and want to walk away completely, put the novation in writing and get the other party’s explicit consent. A bare assignment, without that release, leaves the assignor exposed if the assignee fails to perform.