by Patricia M. Wagner and Ross K. Friedberg
Among the criteria that the “Proposed Statement of Antitrust Enforcement Policy Regarding Accountable Care Organizations Participating in the Medicare Shared Savings Program” (“Proposed Statement”) uses to evaluate an accountable care organization’s (“ACO’s”) risk of an antitrust challenge is the ACO applicant’s “market share” within each of its service lines. The market share is a measure of the share of services an ACO participant provides in its Primary Service Area (“PSA”) relative to other providers. The share of services that each ACO participant provides in its PSA is the key factor that the agencies are proposing to use for determining whether an ACO will receive “Safety Zone” protection from the antitrust laws or be subject to mandatory expedited review from the agencies in order to participate in the Medicare Shared Savings Program. To assist with the PSA analysis, we have provided in this alert a step-by-step description of the proposed method for calculating PSA shares as well as an illustration of the steps involved in calculating PSA shares.