An agency relationship is created in five recognized ways: express agreement, implied conduct, ratification, estoppel, and necessity. Each method produces the same core result — one person (the principal) authorizes another (the agent) to act on their behalf, and the agent takes on fiduciary duties of loyalty, care, and honest dealing. The method matters because it shapes the scope of the agent’s power and how easily third parties can rely on it.
Express Agreement
The most straightforward route is an explicit arrangement in which the principal spells out the agent’s authority, either spoken or written. A handshake deal between a business owner and a sales representative qualifies, but written agreements are far more common because they reduce disputes about what the agent was actually allowed to do. The most recognizable example is a power of attorney, which authorizes a named individual to handle financial transactions, sign documents, or manage property on the principal’s behalf. A power of attorney usually needs to be notarized to be legally effective.
One important wrinkle is the Equal Dignities Rule. If the contract the agent will be signing must be in writing under the Statute of Frauds — real estate sales, leases longer than a year, contracts that can’t be performed within a year — then the agent’s authorization must also be in writing. A verbal “go ahead and sell my house” won’t cut it. Without written authorization, the underlying contract can be challenged as voidable.
General Agents Versus Special Agents
Express agreements can create two distinct types of agents. A general agent has broad, ongoing authority to handle a range of business on the principal’s behalf. A property manager who collects rent, arranges repairs, and signs service contracts under a single appointment is a general agent. A special agent, by contrast, is authorized to handle only a specific transaction or a narrow set of tasks. A real estate broker hired to find a buyer for a single parcel of land is a classic special agent: they can market the property and identify buyers, but they typically have no authority to sign the sale contract themselves.
The distinction has practical consequences. Third parties can generally assume a general agent has the authority typical for that role, even if the principal privately imposed restrictions. With a special agent, third parties are expected to verify what the agent is actually authorized to do.
Implied Agency Through Conduct
Not every agency starts with a conversation about authority. When a principal’s behavior signals that someone has permission to act for them, and the agent behaves accordingly, courts will find an implied agency even without a formal agreement. Consider a shop owner who lets a friend regularly place supply orders and pays the invoices without objection for months. No one ever said “you’re my agent,” but the pattern of conduct creates the relationship all the same.
Implied authority also fills in gaps within an existing agency. An agent authorized to manage a retail store has the implied power to do what a store manager would normally do — order inventory, schedule staff, handle customer complaints — even if the principal never specifically mentioned those tasks. Courts look at what’s customary for someone in that position. The principal is bound by those actions because they’re a natural extension of the authority actually granted.
A principal can stop implied authority from expanding by explicitly prohibiting certain actions. If the store owner tells the manager “never order from Supplier X,” the manager has no implied authority to do so, even if other managers in similar stores routinely order from that supplier.
How Apparent Authority Differs
Implied authority and apparent authority are easy to confuse, but they work differently. Implied authority is real authority that flows from the principal’s relationship with the agent; it fills in the reasonable gaps of what the agent was asked to do. Apparent authority isn’t real authority at all. It exists in the eyes of a third party who reasonably believes the agent has power based on what the principal did or said publicly.
The “power of position” is a common source of apparent authority. When a company gives someone the title of “Vice President of Purchasing,” outside vendors will reasonably assume that person can commit the company to supply contracts, even if the company internally limited the VP’s spending to $5,000. If the principal never communicated that restriction to the vendors, the principal is stuck with the contracts the VP signed. Private limitations on an agent’s authority don’t protect the principal against third parties who had no way to know about them.
Agency by Ratification
Sometimes a person acts on someone else’s behalf without permission, and the supposed principal later decides to accept the deal. That acceptance is called ratification, and it retroactively creates an agency relationship as if the authority had existed from the start.
Ratification has strict requirements. The person who acted must have claimed to be representing the principal at the time; someone acting purely on their own with no mention of the principal can’t be ratified later. The principal must have existed and been legally capable of doing the act when it originally happened. And critically, the principal must know all the material facts about the transaction before accepting it. If an employee sells company equipment for $5,000 without authorization, the owner can ratify the sale, but only if the owner knows the price, the buyer, and the terms before agreeing. Accepting payment while aware of those details seals the deal.
Once ratified, the legal effect reaches back to the moment of the original transaction. The agent is treated as having had authority all along, and the third party’s rights are locked in from that earlier date.
No Cherry-Picking Allowed
A principal cannot ratify only the favorable parts of an unauthorized deal while rejecting the rest. If an employee negotiated a supply contract that includes both a good price and a burdensome return policy, the principal either ratifies the entire contract or rejects it entirely. Courts have consistently held that ratifying part of a transaction means ratifying the whole thing. This prevents principals from waiting to see how a deal plays out and then selectively claiming the profitable pieces.
Agency by Estoppel
Estoppel doesn’t create a true agency. It prevents the principal from denying one exists when their behavior misled a third party. If a company allows someone to act as its representative and a customer reasonably relies on that appearance, the company can’t later say “that person had no authority” to avoid the obligation.
Three elements have to line up: the principal’s conduct, the third party’s reasonable belief, and actual harm from relying on that belief. Suppose a customer pays a $1,000 deposit to someone sitting behind the company’s front desk, wearing its uniform, and using its receipts. If the company knew this was happening and did nothing to correct the impression, a court will treat the transaction as valid even if the person behind the desk was never formally appointed as an agent. The company’s silence created the problem, so the company bears the loss.
Estoppel protects third parties, not the supposed agent. The “agent” in an estoppel situation gains no independent rights against the principal. The doctrine exists solely to prevent the principal from using another person’s lack of authority as a shield after behaving as though authority existed.
Agency by Necessity
This is the rarest method and arises only in genuine emergencies. When someone has possession of another person’s property and must act immediately to prevent its destruction or serious loss, the law recognizes an agency relationship even though no one agreed to one.
Four conditions must align. There must be an actual emergency requiring immediate action. The person acting must have no prior authorization. They must be unable to reach the principal for instructions. And the action taken must be reasonable under the circumstances. A warehouse operator whose refrigeration fails overnight, with the owner unreachable, can sell perishable inventory rather than watch it spoil. The sale is treated as an authorized act because the alternative was total loss.
Courts scrutinize these claims closely. If the person could have waited, could have contacted the principal, or took action that wasn’t proportionate to the emergency, the necessity defense falls apart. It isn’t a general license to act on someone else’s behalf whenever you think it’s a good idea. It’s a narrow safety valve for situations where doing nothing would be worse.
Duties That Attach Once the Relationship Exists
Regardless of which of the five methods creates the relationship, the agent immediately owes the principal a set of fiduciary duties. These aren’t optional add-ons. They’re baked into the relationship itself.
- Loyalty: the agent must act solely in the principal’s best interest, not their own. An agent who secretly profits from a transaction or competes with the principal breaches this duty even if the principal suffers no financial loss.
- Obedience: the agent must follow the principal’s reasonable instructions. Deviating from those instructions, even with good intentions, can make the agent personally liable for any resulting damage.
- Care: the agent must act with the competence and diligence that a reasonable person in that position would exercise.
- Disclosure: the agent must share any information the principal would want to know, especially facts that could affect the principal’s decisions.
- Accounting: the agent must keep accurate records of all transactions handled on the principal’s behalf and must not mix the principal’s funds or property with their own.
The principal also owes duties to the agent, including paying the agent as agreed, reimbursing authorized expenses, and not interfering with the agent’s ability to perform. These mutual obligations are what distinguish an agency from a casual favor, and they attach the moment any of the five formation methods takes hold.