It is normally said that it is a breach of an agent's duty to act for competing principals. In the course of acting for each of their principals, estate agents will acquire information confidential to that principal. It cannot be sensibly suggested that an estate agent is contractually bound to disclose to any one of his principals information which is confidential to another of his principals. The position as to confidentiality is even clearer in the case of stockbrokers who cannot be contractually bound to disclose to their private clients inside information disclosed to the brokers in confidence by a company for which they also act. Accordingly in such cases there must be an implied term of the contract with such an agent that he is entitled to act for other principals selling competing properties and to keep confidential the information obtained from each of his principals.
Similar considerations apply to the fiduciary duties of agents.
There is a strict duty not to profit from a position of trust, or, as it is sometimes relevant to put it, not to allow a conflict to arise between duty and interest, is one of strictness. The rule retains its vigour in all jurisdictions where the principles of equity are applied. But one can no more deduce an individual's duties in concrete circumstances from the concept of a trust than one can from the concept of a contract. The rule has different applications in different contexts. It applies, in principle, whether the case is one of a trust, express or implied, of partnership, of directorship of a limited company, of principal and agent, or master and servant, but the precise scope of it must be moulded according to the nature of the relationship.