The Acronyms in Your Contract Inbox: NDA, MOU, LOI, SOW, MSA

Contract email runs on initials. A thread arrives asking you to sign one document, review another and attach a third, and the letters do most of the talking. They look like variations on the same thing, but each one answers a different question: whether you are bound, what work is promised, and which obligations outlast the project.

Here are five common ones, with what they actually contain. The legal examples below are US-focused, and they sit alongside the rest of the online business terms in the dictionary.

NDA: non-disclosure agreement

An NDA restricts what one or both parties may do with information they receive. You will also see confidentiality agreement, MNDA when the obligation runs both ways, and "NDA'd" used as a verb. The same three letters cover documents with very different scopes: one signed by a co-founder, one signed by a contractor before they get repository access, and one attached to a commercial negotiation are not the same agreement.

The distinction worth knowing is that an NDA has two clocks. There is the term of the agreement, which is how long the arrangement itself runs, and there is the survival period, which is how long the confidentiality obligation continues after the agreement ends. A two-year mutual NDA can carry a five-year survival period for anything disclosed during it, which is why "it expired" and "I can talk about it" are different claims.

Ranges vary by subject matter. Commercial NDAs commonly set terms in the low single-digit years, an NDA can be perpetual where the material justifies it, and information with a short shelf life, such as a pricing sheet or a roadmap, tends to get a shorter window.

Some state law limits the far end. Where a confidentiality restriction falls within Florida's restrictive covenant statute, section 542.335 sets rebuttable duration presumptions that differ by circumstance and directs the court to modify an unreasonable restraint to the relief reasonably necessary. That statute is about restraints affecting competition, so it is not a general expiry rule for every confidentiality clause.

MOU: memorandum of understanding

An MOU records an understanding between parties, often while details are still being worked out. It may set out preliminary intentions, binding commitments, or a mixture of both, and the title tells you nothing about which.

Enforceability comes from content. The Legal Information Institute lists the elements of a contract as mutual assent, consideration, capacity, and legality, and notes that informal agreements can be binding where those are present. An MOU that fixes a price, a date, and a promise to pay can behave like a contract. The practical answer is to state inside the document which clauses bind and which do not.

LOI: letter of intent

An LOI describes a transaction the parties are moving toward, most commonly an acquisition, a commercial lease or an investment. It is not a later step after an MOU. The two overlap, and which one appears depends on habit and sector: MOUs are common between organizations setting up ongoing cooperation, while LOIs are used when two sides are working toward a specific deal.

Many LOIs are drafted as largely non-binding, with particular provisions that do bind, exclusivity and confidentiality being the usual ones, along with who carries which costs. The binding provisions are not always grouped in one place, so identify each one by what it says rather than where it sits, and follow its cross-references, since a binding clause often points to definitions elsewhere in the document.

SOW: statement of work

The SOW describes the work itself. Federal procurement supplies a useful checklist rather than a universal definition: under FAR 8.405-2, a statement of work in that ordering context covers a description of work to be performed, location of work, period of performance, deliverable schedule, applicable performance standards, and any special requirements.

Commercial SOWs cover similar ground. "Scope of work" is sometimes used for the same document and sometimes for the work-description portion inside a broader SOW, and usage varies between industries, so it is worth asking which the sender means. Disputes tend to turn on the specifics rather than the summary: whether acceptance criteria were met, how many revision rounds were included, and whether a mid-project request was a clarification or new work.

MSA: master service agreement

An MSA, also written as a master services agreement, covers the terms both sides don't want to renegotiate per project: liability limits and caps, payment timelines, confidentiality, ownership of what is produced, insurance, dispute resolution, and termination rights.

The SOW covers the project-specific layer. Deliverables, schedule, named personnel, acceptance criteria, and price belong there, which is why one MSA can sit above several SOWs. Check the MSA's term and what happens at the end of it, since renewal handling differs between agreements, and check what it says about conflicting documents. A precedence clause commonly provides that the MSA controls where a SOW term contradicts it, so a favorable SOW clause may simply not apply.

Related initials in the same threads

• T&Cs, terms and conditions, the standard terms a provider applies to its customers, whether signed, referenced or presented online
• SLA, service level agreement, the availability and response commitments for a service, sometimes a schedule to a larger agreement and sometimes standalone
• PO, purchase order, a buyer's order for goods or services, which can carry contractual significance once it is accepted
• DPA, data processing agreement, the terms governing personal data that one party processes for another, required in specific forms under some data protection regimes
• IP assignment, the clause or separate document transferring ownership of work created
• NNN, a non-disclosure, non-use and non-circumvention agreement, used in overseas manufacturing

What to check before signing

Three questions do most of the work. Is this document meant to bind you, and does its content match that intent? Which document controls if two of them conflict? And what survives the end of the relationship?

That last one is the least visible. Look for the survival clause, then confirm how long confidentiality continues after termination, whether the assignment of work already delivered is permanent, whether payment obligations for accepted deliverables outlast a cancellation, and whether any non-solicitation or exclusivity terms keep running. The acronym in the subject line tells you which document you have. The survival clause tells you what you still owe next year.