- Unrestricted endowment can be used in any way the recipient chooses to carry out its mission.
- Term endowment funds stipulate that all or part of the principal may be expended only after the expiration of a stated period of time or occurrence of a specified event, depending on donor wishes.
- Quasi endowment funds must retain the purpose and intent as specified by the donor or source of the original funds and earnings may be expended only for the specified purpose.
Endowment revenue can be restricted by donors to serve many purposes. Endowed professorships or scholarships restricted to a particular subject are common; in some places a donor could fund a trust exclusively for the support of a pet.
 Ignoring the restriction is called "
invading" the endowment.
 But change of circumstance or financial duress like bankruptcy can preclude carrying out the donor's intent. A court can alter the use of restricted endowment under a doctrine called
cy-près meaning to find an alternative "as near as possible" to the donor's intent.
 The restricted/unrestricted distinction focuses on the use of the funds; see quasi-endowment below for a distinction about whether principal can be spent.