1. A fiduciary duty, owed as a result of:
a historically recognized fiduciary relationship existing as a matter of course within the traditional categories of trustee-cestui que trust, executor-beneficiary, solicitor-client, agent-principal, director-corporation, and guardian-ward or parent-child; or
an ad hoc fiduciary relationship, established on a case-by-case basis, with the following elements: (1) an undertaking by the alleged fiduciary to act in the best interests of the alleged beneficiary or beneficiaries; (2) a defined person or class of persons vulnerable to a fiduciary's control (the beneficiary or beneficiaries); and (3) a legal or substantial practical interest of the beneficiary or beneficiaries that stands to be adversely affected by the alleged fiduciary's exercise of discretion or control.
2. A breach of the fiduciary duty, consisting of an act of disloyalty in which the fiduciary, acting out of self-interest, does something that is, or is presumed to be, detrimental to the interests of the beneficiary.
Alberta v. Elder Advocates of Alberta Society, 2011 SCC 24, at paras. 22, 33 and 36.