In this study, we investigate the types of overlay provisions used in public school funding and the impacts that these provisions can have on equity, fiscal neutrality, and adequacy in school funding. We begin by reviewing the various overlay provisions that could be used by states. We then turn to an analysis of Indiana's 2004 foundation aid program and the impact of the state's three different overlay provisions on the level and distribution of education funding received by districts and, in particular, on horizontal and vertical equity and fiscal neutrality. Our results show that these provisions led directly to horizontal and vertical inequity in the state's funding formula and yet resulted in improvements in fiscal neutrality. Removing these provisions, however, would likely harm many districts with falling enrollments. (Contains 9 tables and 6 footnotes.)