Title XII of the Pension Protection Act of 2006, Pub. L. 109-280, 120 Stat. 780 (2006) (the PPA) made numerous changes to provisions of the Internal Revenue Code (the Code) addressing charitable giving and tax-exempt organizations. Particular changes to the law were made regarding supporting organizations (SOs) and charitable giving arrangements commonly referred to as donor advised funds (DAFs). The legislation provided a statutory definition of the term “donor advised fund” and modified the statutory definition of “supporting organization.” Section 1226 of the PPA directs the Secretary of the Treasury to undertake a study on the organization and operation of SOs and DAFs and submit the findings to Congress. This report provides the results of Treasury’s analysis of SOs and DAFs and responds to the questions posed by Congress.