Since 2007, attention has been focused on nursing home ownership by private investment (PI) firms. Nursing home providers are required to disclose parties with an ownership or control interest in order to participate in Medicare or Medicaid. The Centers for Medicare & Medicaid Services (CMS) maintains ownership and chain data in its Provider Enrollment, Chain, and Ownership System (PECOS). This report examined: (1) the extent of PI nursing home ownership and firms' involvement in homes' operations; (2) whether PECOS reflects PI ownership; and (3) how states use ownership data for oversight. Includes recommendations. Charts and tables. A print on demand publication.