4.100 NPISHs are entities mainly engaged in providing goods and services to households or the community at large free of charge or at prices that are not economically significant (and thus are classified as nonmarket producers), except those that are controlled and mainly financed by government units. Examples include charities, relief and aid organizations financed by voluntary transfers, as well as trade unions, professional or learned societies, consumers’ associations, religious institutions, and social, cultural, and recreational clubs that do not charge economically significant prices. They may be corporations, foundations, trusts, or other unincorporated entities.
4.101 NPISHs are mainly financed from contributions, subscriptions from members, or earnings on holdings of real or financial assets. The NPISH sector is a subset of nonprofit institutions. Those that charge economically significant prices are included in the financial or nonfinancial corporations or households sectors, as relevant. Additionally, nonprofit institutions serving businesses, such as chambers of commerce and trade associations, are included in the corporations sectors. When this Manual refers to nonprofit institutions, it includes all nonprofit institutions.
Paragraph 4.100 - 4.101, Page 68 BPM6
For more info : Balance of Payments and International Investment Position Manual - Sixth Edition (BPM6)