Under ERISA, a fiduciary is any person, company, or association that renders investment advice for a fee or other compensation with respect to the funds or property of a plan, or who has the authority to do so. A fiduciary exercises discretionary authority or control over the management of a plan or the management of the disposition of its assets, or has the discretionary authority or responsibility in administering a plan. Importantly, a fiduciary is bound to always act in the best interests of their clients.