Understanding Express, Implied, and Quasi-Contracts

Running a business means entering into agreements constantly — with customers, suppliers, contractors, and partners. Many of these agreements are obvious and written down, but others are based on conduct or created later by courts to prevent unfair outcomes. In legal terms, these arrangements are described as express contracts, implied contracts, and quasi-contracts.

This article explains how each type of contract works, how they are formed, and why understanding the differences can protect your small business from disputes, unexpected liability, and unjust enrichment.

Core Idea: What Makes Something a “Contract”?

Before separating express, implied, and quasi-contracts, it helps to understand what courts look for when determining whether a contract exists in the first place. Under U.S. contract law, most contracts rest on a few core elements:

• Offer – One party proposes specific terms (for example, “I will deliver 100 units for $1,000”).
• Acceptance – The other party agrees to those terms.
• Consideration – Each side gives or promises something of value in return (money, services, goods, or forbearance).
• Mutual assent – There is a shared understanding that an agreement has been formed.
• Legal enforceability – The agreement is not illegal and is definite enough that a court can enforce it.

Express and implied contracts both rely on these elements, but differ in how the parties communicate their agreement. Quasi-contracts are different: they do not require agreement at all, because they are obligations imposed by law to prevent unjust enrichment.

Express Contracts: Agreements in Words

An express contract is the most familiar type of contract. The parties state their agreement in words — either in writing or verbally — and spell out the duties, rights, and remedies that apply.

Key Features of Express Contracts

• Clear communication: Terms such as price, timing, scope of work, and remedies are explicitly stated.
• Written or oral: The agreement can be on paper, in email, or spoken, as long as terms are clear enough to be understood.
• Ease of proof: Because terms are documented or recorded, it is typically easier to prove what the parties agreed to and enforce the contract.

Written contracts are generally preferred in business because they offer clearer evidence and greater protection. In many commercial contexts, written agreements reduce the risk of disputes and make litigation more predictable.

Why Express Contracts Matter to Small Businesses

For small businesses, express contracts are crucial in relationships such as:

• Vendor agreements for supplies or inventory
• Service contracts with clients
• Employment and independent contractor agreements
• Leases for premises and equipment

When these agreements are express and documented, the business can more easily prove terms like price, deadlines, and responsibilities in court if a dispute arises.

Advantages and Limitations

Implied Contracts: Agreements Based on Conduct

An implied contract is not written down or explicitly stated, yet the law treats it as binding because the parties’ behavior shows that they intended to enter into an agreement.

Courts recognize two main types of implied contracts:

• Implied-in-fact contracts – Actual contracts inferred from the conduct of the parties.
• Implied-in-law obligations (quasi-contracts) – Legal obligations imposed to prevent unjust enrichment, not true contracts.

Implied-in-Fact Contracts: Silent but Real Agreements

An implied-in-fact contract arises when the parties’ actions and circumstances demonstrate a mutual intent to contract, even though they never explicitly said, “We agree” in words.

Typical Elements of an Implied-in-Fact Contract

• Benefit conferred: One party provides goods, services, or value to another.
• Expectation of compensation: The provider reasonably expects to be paid or compensated.
• Opportunity to reject: The recipient has a chance to decline the benefit but accepts or uses it.
• Mutual assent through conduct: A reasonable observer would conclude that both sides intended an agreement.

These elements make the implied-in-fact contract enforceable in much the same way as an express contract; the difference lies in how the agreement is demonstrated.

Business Examples of Implied-in-Fact Contracts

• A consultant repeatedly provides services to a client who regularly pays invoices, even though there is no written contract.
• A customer routinely orders goods from a supplier following an established pattern, and the supplier fulfills orders without a formal agreement.
• A tenant stays in a commercial space after a lease expires and continues paying rent, with the landlord accepting payments.

In each case, the implied-in-fact contract is based on conduct: both sides behave as if a contract exists, creating obligations despite the absence of a written agreement.

Enforceability and Risks of Implied Contracts

Courts generally treat implied-in-fact contracts as legally binding, but they are often more difficult to prove than express contracts because they rely on circumstantial evidence.

Key risks include:

• Unclear terms: Price, scope, and timelines may be disputed because they were never explicitly stated.
• Limited recovery: Courts may award only the reasonable value of services, not what one party hoped to earn.
• Overlap with express contracts: If an express contract covers the relationship, courts are less likely to recognize a separate implied contract for the same subject matter.

Quasi-Contracts: Legal Obligations to Prevent Unjust Enrichment

Quasi-contracts, sometimes called contracts implied in law or constructive contracts, are not true contracts based on agreement. Instead, they are legal obligations imposed by courts to prevent one party from being unjustly enriched at another’s expense.

Defining Quasi-Contract

According to leading legal sources, a quasi-contract is a legal obligation imposed by law to prevent unjust enrichment where no express or implied-in-fact contract exists. Courts may presume such an obligation when one party has received a benefit in circumstances where it would be inequitable not to pay for it.

Essential Elements of Quasi-Contract

• Benefit conferred: The plaintiff provides a benefit to the defendant.
• Knowledge and appreciation: The defendant is aware of the benefit and retains it.
• Inequitable retention: Keeping the benefit without paying would be unfair or unjust.

If these elements are present and no valid express or implied-in-fact contract governs the situation, a court may impose a quasi-contractual obligation. The usual remedy is restitution or recovery of the reasonable value of the benefit provided, often under a theory known as quantum meruit (“as much as is deserved”).

Quasi-Contract vs. Implied-in-Fact: Key Differences

When Courts Use Quasi-Contracts

Courts typically resort to quasi-contractual relief when:

• No valid express or implied-in-fact contract governs the dispute.
• One party has conferred a non-gratuitous benefit expecting compensation.
• The other party has retained that benefit, and allowing them to keep it without payment would result in unjust enrichment.

Importantly, if an express contract or an implied-in-fact contract already covers the same subject matter, courts usually reject quasi-contract claims to avoid duplicating or undermining the existing agreement.

Comparing Express, Implied, and Quasi-Contracts

For business owners, the practical question is not just how these contracts are defined, but how they differ in formation, proof, and remedies.

Practical Tips for Small Businesses

Understanding these distinctions helps business owners reduce risk and manage relationships more effectively.

Minimize Reliance on Implied Agreements

• Document key deals: Put important terms in writing, even if the relationship begins informally.
• Clarify expectations early: Discuss price, scope, timelines, and payment conditions at the outset.
• Update contracts as relationships evolve: If practices change, revise or supplement express agreements to match reality.

Manage the Risk of Quasi-Contract Claims

• Avoid accepting unsolicited benefits: If you receive services you did not request, clearly reject them where possible.
• Respond promptly to invoices: Dispute invoices in writing if you believe no contract exists, rather than ignoring them.
• Review gaps in existing contracts: Ensure express agreements cover likely scenarios, reducing the need for courts to impose equitable remedies.

When to Seek Legal Advice

Business owners should consider consulting a lawyer when:

• A major relationship has been operating on handshake terms or a series of emails.
• There is a dispute about whether a contract exists or which terms apply.
• Someone claims compensation based on unjust enrichment or quantum meruit.

Legal counsel can help determine whether there is an express contract, an implied-in-fact contract, or grounds for quasi-contractual relief, and what remedies might be available.

Frequently Asked Questions

Are implied contracts just as enforceable as express contracts?

In many cases, yes. Courts treat implied-in-fact contracts as binding when the parties’ conduct demonstrates mutual assent, offer, acceptance, and consideration. However, proving the precise terms can be more challenging than with a written express contract.

Can a quasi-contract exist when there is already a written agreement?

Generally, no. If an express contract governs the relationship and subject matter, courts usually do not impose a quasi-contract for the same issues. Quasi-contract is reserved for situations where no valid contract exists and unjust enrichment would otherwise occur.

Is an oral contract considered an express contract?

Yes. Express contracts can be written or oral, as long as the parties’ agreement is clearly communicated in words. Some types of contracts, such as those involving real estate or certain large transactions, may need to be in writing to be enforceable under specific statutes.

What is quantum meruit and how does it relate to quasi-contracts?

Quantum meruit refers to recovery of the reasonable value of services or benefits provided. In quasi-contract cases, courts often award quantum meruit as a form of restitution to prevent unjust enrichment when no traditional contract exists.

Can an implied contract later be turned into an express contract?

Yes. Parties can formalize an implied-in-fact relationship by putting their existing practices and expectations into a written or oral express agreement. Doing so usually clarifies obligations and reduces the risk of future disputes.

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Author

medha deb

 

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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