Guardian is an individual who has a fiduciary responsibility for another usually a minor.
Applying "Guardian" to Securities Exams:
In the case of minors, guardians are most often parents. However, a guardian can be any adult who has been appointed by the court to look out for the best interests of another person. For example, if a person has been deemed mentally incapacitated by a court, a guardian will be appointed to act as a fiduciary for that person. Furthermore, if the mentally incapacitated person owns securities, an account must be opened for that person, naming the guardian as the person with trading authorization, within 60 days of the court order.