What is the test for a constructive trust?

49 The maintenance of the integrity of market-driven institutions is a legitimate objective of constructive trusts. The defendants (in particular Lions) owed fiduciary duties to the plaintiffs which were breached, entitling the plaintiffs to a declaration of a constructive trust. All four criteria for the imposition of a constructive trust as enunciated in Soulos v. Korkontzilas are met on the facts of this case (at para. 45): (1) The defendant must have been under an equitable obligation, that is, an obligation of the type that courts of equity have enforced, in relation to the activities giving rise to the assets in his hands; (2) The assets in the hands of the defendant must be shown to have resulted from deemed or actual agency activities of the defendant in breach of his equitable obligation to the plaintiff; (3) The plaintiff must show a legitimate reason for seeking a proprietary remedy, either personal or related to the need to ensure that others like the defendant remain faithful to their duties and; (4) There must be no factors which would render imposition of a constructive trust unjust in all the circumstances of the case; e.g., the interests of intervening creditors must be protected.