https://en.wikipedia.org/wiki/United_States_House_Select_Com...

  In April 1952, the Select Committee to Investigate Tax-Exempt Foundations and Comparable Organizations.. began an investigation of the "educational and philanthropic foundations and other comparable organizations which are exempt from federal taxes to determine whether they were using their resources for the purposes for which they were established..

  In April 1954, the House authorized the Reece Committee. Unlike its predecessor, which limited its attention to generalities, the Reece Committee mounted a comprehensive inquiry into both the motives for establishing foundations and their influence on public life. 

Final report (2000 pages): https://archive.org/details/full-reece-committee-investigati...