The broker is a fiduciary with a duty of loyalty and an obligation to act in the best interests of the principal, to whom the broker must disclose all material information that it may possess or obtain concerning the transaction. Where the broker's interests or loyalties are divided due to a personal stake in the transaction or the representation of multiple parties, the broker must disclose to the principal the nature and extent of the broker's interest in the transaction or the material facts of the broker's divided loyalties. A breach of the broker's duty of loyalty may constitute a fraud for which the broker is answerable in damages.
Edwards v. Walsh, NY Slip Op 01197 (2d Dep't February 20 2019)
Here is the decision.