A fiduciary duty is the highest duty imposed by law, and while there are many types of fiduciary relationships, the definition is very broad. Generally speaking, a fiduciary duty exists between a fiduciary and a trustee. The fiduciary is expected to act in the best interest of the trustee. This relationship applies to lawyers and clients, doctors and patients, and legal guardians and their wards. However, these are all very different relationships, so a one size fits all approach to the handling of a fiduciary duty can often lead to litigation. But, the definition of fiduciary duty could see some changes in the near future when it’s applied to brokers and investors.