According to the 1986 Amendment to the False Claims Act, almost any person, corporate organization or government entity can be charged as a defendant. The only exceptions are certain public officials such as members of Congress, judges and senior executive branch officials. Generally, government employees can also be charged.

Some of the more common defendants in qui tam actions are:

Government Contractors and Subcontractors: The most common defendant in qui tam actions. Subcontractors can be charged if they cause a false claim to be presented to the Government through a contractor.

Medical Providers: Another common defendant in qui tam actions involving Medicare/Medicaid fraud. Includes doctors, hospitals, HMOs, and clinics.

Private Universities: Private universities have been charged as defendants in qui tam actions that involves their handling of federal grants and research and development money.

State and Local Government Agencies and Officials: Because they are recipients of large amounts of federal money, state and local entities can be defendants in qui tam actions. This also includes state run universities and colleges.

In general, any organization or person who uses federal money can be charged as a defendant in a qui tam action