This paper discusses the duties of a fiduciary with respect to underperforming assets held in a client’s account. A trustee, investment adviser, and investment manager each is a fiduciary. Because trust law most clearly articulates fiduciary rules, this paper focuses on trust law as the principal foundation of fiduciary law. Although investment advisers are not strictly subject to trust law, the fiduciary investment principles applicable to advisers are very similar to those governing trustees. Accordingly, this paper discusses the legal framework and principles applicable under trust law generally with respect to the investment and management of trust assets, focusing specifically on the treatment of assets that underperform based on relevant measures of investment performance. These general principles may apply differently to investment advisers depending on the facts and circumstances.