Fiduciary abuse can be practiced by agents such as a financial advisor, or power of attorneys. Examples include a financial advisor borrowing funds from client's account in order to take speculative positions in securities, or even a close family member (acting as power of attorney) misrepresenting a legally incapacitated family member as a way to steal assets.
People can protect themselves from fiduciary abuse by taking an active role in their money management or by setting up an irrevocable trust.