A private foundation is a legal entity set up by an individual, a family or a group of individuals, for a purpose such as philanthropy or an object legal in the economic operation. The Bill & Melinda Gates Foundation is the largest private foundation in the U.S. with over $38 billion in assets. However, most private foundations are much smaller and approximately two-thirds of more than 84,000 filing with the IRS in 2008 have less than $1 million in assets and 93% have less than $10 million. In aggregate, private foundations in the U.S. control over $628 billion in assets and made more than $44 billion in charitable contributions in 2007.
Unlike a charitable foundation, a private foundation does not generally solicit funds from the public.
Not all foundations engage in philanthropy. Private foundations are often used for estate planning purposes.
One of the characteristics of the legal entities existing under the status of "Foundations" is a wide diversity of structures and purposes. Nevertheless, there are some common structural elements that are the first observed under legal scrutiny or classification.
- Legal requirements followed for establishment
- Purpose of the foundation
- Economic activity
- Supervision and management provisions
- Accountability and auditing provisions
- Provisions for the amendment of the statutes or articles of incorporation
- Provisions for the dissolution of the entity
- Tax status of corporate and private donors
- Tax status of the foundation
Some of the above must be, in most jurisdictions, expressed in the document of establishment. Others may be provided by the supervising authority at each particular jurisdiction.
Common law 
A private foundation, in the United States, is a charitable organization described in the Internal Revenue Code by section 509. A private foundation is necessarily a 501(c)(3) exempt organization (or a former such entity). It is defined by a negative definition: by what it is not. A private foundation is not a public charity, as described in section 170(b)(1)(A) (i) through (vi). Neither is it a section 509(a)(2) organization, nor a supporting organization. Private foundations are subject to 2% excise taxes found in section 4940 through 4945 of the internal revenue code. Once a charity becomes a private foundation, it retains that status unless it follows the difficult termination rules of section 507.
Civil law 
The following foundations are set up under civil law legal systems:
The Austrian Private Foundation (Privatstiftung) was last reformed under the Private Foundation Act in September 1993.
The Liechtenstein Family Foundation (Stiftung) was first introduced in 1926.
The Mauritius Foundation was introduced following 'The Foundations Act' of 2012.
A foundation in the Netherlands (Stichting) is a legal person created through a legal act. This act is usually either a notarised deed (or a will) that contains the articles of the foundation which must include the first appointed board. No government authority is involved in the creation or authorization of a foundation, it acquires full legal capacity through its sole creation. A foundation has no members and its purpose must be stated in its articles, using capital dedicated to such goal. The foundations are defined in the Dutch Civil Code (Burgerlijk Wetboek), Boek 2 Art 285-304. It is not necessary in the Netherlands that a foundation serves a purpose of general interest, but its official goal cannot include making payments to anybody, except for charitable causes. The foundations are governed and represented by a board that is responsible for its administration, this board has not a requirement for specific number of members.
Art. 2:289 of the Civil Code establishes that all foundations must be registered in the Register of Commerce or "Handelsregister". Commercial activities are allowed if they are within the purpose of the foundation and are taxed. Board members can be held liable for the foundation, civilly as well as criminally.
The Dutch Tax Service can declare an institution to be an "institution for general benefit" (algemeen nut beogende instelling, ANBI), with tax benefits. Often, but not necessarily, this is a foundation. Conversely, not every foundation qualifies.
Examples of foundations:
- Cornelis Kruseman Stichting - purpose: bring the work of painter Cornelis Kruseman (1797-1857) to the attention of the public
- Stichting Museumjaarkaart - purpose: promote visits to Dutch museums
- Nederlandse Omroep Stichting - purpose: make news and sports programmes for the three Dutch public television channels and the Dutch public radio services
- Stichting FERN - purpose: promote greater environmental and social justice, focusing on forests and forest peoples’ rights
- Stichting Talent-aid International - purpose: promote and support artists, composers and performers mainly via the internet.
- Stichting INGKA Foundation - purpose: promote and support innovation in the field of architectural and interior design
- Stichting Max Havelaar - purpose: the Dutch member of Fairtrade International
- Stichting Pensioenfonds ABP - pension fund for the government and educational sectors
- Stichting Pensioenfonds Zorg en Welzijn - pension fund for the healthcare and social work sectors
- Wiardi Beckman Stichting - purpose: a think tank linked to the Labour Party (PvdA)
- Mars One - purpose: establish a permanent human colony on Mars
Netherlands Antilles 
Foundation legislation was last reformed in 1998, giving rise to the Netherlands Antilles Private Foundation (Stichting Particulier Fonds).
The Nevis Multiform Foundation was first introduced in 2005.
The Panama Private Interest Foundation was first introduced in 1995, modelled on the Liechtenstein Family Foundation.
Saint Kitts 
The Saint Kitts Foundation was introduced following the Foundation Act of 2003.
A private foundation in Sweden (Stiftelse) is formed by a letter of donation from a founder donating funds or assets to be administered for a specific purpose. A private foundation may have diverse purposes, including but not limited to collective, familiar, or the purpose of passive administration of funds. Normally, the supervision of a private foundation is done by the county government where the foundation has its domicile, however, large foundations must be registered by the County Administrative Board (CAB), which must also supervise the administration of the foundation. The main legal instruments governing private foundations in Sweden are those that regulate foundations in general: the Foundation Act (1994:1220) and the Regulation for Foundations (1995:1280).
See also