A fiduciary is a person who holds a legal or ethical relationship of trust with one or more other parties (person or group of persons). Typically, a fiduciary prudently takes care of money for another person. One party, for example a corporate trust company or the trust department of a bank, acts in a fiduciary capacity to the other one, who for example has entrusted funds to the fiduciary for safekeeping or investment. Likewise, asset managers—including managers of pension plans, endowments and other tax-exempt assets—are considered fiduciaries under applicable statutes and laws.  In a fiduciary relationship, one person, in a position of vulnerability, justifiably vests confidence, good faith, reliance, and trust in another whose aid, advice or protection is sought in some matter.  In such a relation good conscience requires the fiduciary to act at all times for the sole benefit and interest of the one who trusts.

A fiduciary is someone who has undertaken to act for and on behalf of another in a particular matter in circumstances which give rise to a relationship of trust and confidence.

– Lord Millett, Bristol and West Building Society v Mothew

A fiduciary duty is the highest standard of care at either equity or law. A fiduciary (abbreviation fid) is expected to be extremely loyal to the person to whom he owes the duty (the “principal”): such that there must be no conflict of duty between fiduciary and principal, and they must not profit from his position as a fiduciary (unless the principal consents).

In English common law this relationship is arguably the most important concept within the portion of the legal system known as equity. In the United Kingdom, the Judicature Acts merged the courts of equity (historically based in England’s Court of Chancery) with the courts of common law, and as a result the concept of fiduciary duty also became available in common law courts.

When a fiduciary duty is imposed, equity requires a different, arguably stricter, standard of behavior than the comparable tortious duty of care at common law. It is said the fiduciary has a duty not to be in a situation where personal interests and fiduciary duty conflict, a duty not to be in a situation where their duty conflicts with another fiduciary duty, and a duty not to profit from his fiduciary position without knowledge and consent. A fiduciary ideally would not have a conflict of interest. It has been said that fiduciaries must conduct themselves “at a level higher than that trodden by the crowd” and that “[t]he distinguishing or overriding duty of a fiduciary is the obligation of undivided loyalty”.