Project Summary To inform payment policy that promotes parity, this study examines how voluntary bundled payments impact access and outcomes for racial minorities, ethnic minorities, and individuals with low socioeconomic status (SES), vulnerable groups that have long faced disparities in health care access and outcomes. This application aligns with the Special Emphasis Notice Health Services Research Priorities for Achieving a High Value Healthcare System (NOT-HS-19-011) Priority Area #3: Payment for outcomes. Voluntary bundled payments could exacerbate existing disparities if participating providers perceive that vulnerable patients’ outcomes are difficult to manage and avoid participating in the payment model (i.e., provider selection) or participate but avoid caring for vulnerable groups (i.e., patient selection). It is also vital to understand how impacts on disparities vary based on providers’ mission and experience caring for vulnerable groups (e.g., safety-net vs. non-safety-net providers). Such insights are particularly critical for lower extremity joint replacement (LEJR), congestive heart failure (CHF), and sepsis – the most prevalent procedures and conditions that are both marked by significant, existing disparities and targeted by voluntary bundled payment programs. The insights generated by this proposal are also critical given the impact of COVID-19 on both payment reform and health care disparities. We hypothesize that providers participating in voluntary bundled payment programs will be less likely than non-participants to be located in markets with a high proportion of vulnerable individuals; that disparities in access and outcomes will widen for vulnerable patients, as compared to other patients, after providers start participating in voluntary bundled payments compared to providers that do not participate; that these effects will vary by racial minority versus ethnic minority status, and interactions between racial and ethnic minority status and low SES; and that disparities will widen less at safety-net versus non-safety-net providers.