What are the elements of a breach of fiduciary duty?

Defendants' "cockroach" theory misstates the law. "'The elements of a cause of action for breach of fiduciary duty are the existence of a fiduciary relationship, its breach, and damage proximately caused by that breach.'" (Thomson v. Canyon (2011) 198 Cal.App.4th 594, 604.) Where "'damages are an element of a cause of action, the cause of action does not accrue until the damages have been sustained. [Citation.] "Mere threat of future harm, not yet realized, is not enough."'" (Id. at p. 604.) "'A breach of a professional duty causing only nominal damages, speculative harm, or the threat of future harm that is not yet realized does not suffice.'" (Ibid.)