It sounds likely to be correct to me. All section 501(c)(3) organizations are considered to be private foundations unless they show the IRS that they qualify as public charities under one of the definitions of Section 509(a). Section 509(a)(1) includes churches, schools, hospitals, and other organizations that receive a broad range of support from contributions as described in Section 170(b)(1)(a)(vi), such as a United Way or other organization receiving substantial support from small contributors. Section 509(a)(2) describes organizations that receive most of their support from fees for services, such as nursing homes. (See Ready Reference Pages "Calculating Public Support Percentage.") Section 509(a)(3) organizations are “supporting organizations” supporting 509(a)(1) or 509(a)(2) organizations or public agencies. (See Ready Reference Page "Supporting Organizations are Public Charities.") Supporting organizations, and especially Type III supporting organizations, have been subjected to significant new restrictions by the Pension Protection Act of 2006. (See Ready Reference Page: "Congress Passes Charitable Reforms.")