Most oral agency contracts are legally binding; the law does not require that they be reduced to writing. In practice, many agency contracts are written to avoid problems of proof. And there are situations where an agency contract must be in writing: (1) if the agreed-on purpose of the agency cannot be fulfilled within one year or if the agency relationship is to last more than one year; (2) in many states, an agreement to pay a commission to a real estate broker; (3) in many states, authority given to an agent to sell real estate; and (4) in several states, contracts between companies and sales representatives.
Even when the agency contract is not required to be in writing, contracts that agents make with third parties often must be in writing. Thus Section 2-201 of the Uniform Commercial Code specifically requires contracts for the sale of goods for the price of five hundred dollars or more to be in writing and “signed by the party against whom enforcement is sought or by his authorized agent.”