The Office of Inspector General of the U.S. Department of Health and Human Services (OIG) recently posted its first advisory opinion interpreting a gainsharing arrangement – that is, a financial relationship under which providers share in cost-savings – since passage of the Medicare Access and CHIP Reauthorization Act of 2015 (MACRA). The opinion, Advisory Opinion 17-09 (the “Opinion”), marks the OIG’s first interpretation of the Civil Monetary Penalties Law (CMP) since MACRA amended the law to limit the prohibition on gainsharing arrangements to those involving reductions or limits in medically necessary services, as opposed to all services, including medically unnecessary services.