Therefore, we are proposing to identify an ACO operationally as a collection of

Medicare enrolled TINs. More specifically, an ACO will be identified operationally as a

set of one or more TINs currently practicing as a "group practice arrangement" or in a

"network" such as where "hospitals are employing ACO professionals" or where there are

"partnerships or joint ventures of hospitals and ACO professionals" as stated under

section 1899(b)(1)(A) through (E) of the Act. For example, a single group practice that

participates in the Shared Savings Program would be identified by its TIN. A network of

independent practices that forms an ACO would be identified by the set of TINs of the

practices constituting the ACO. We are proposing to require that organizations applying

to be an ACO provide their ACO participant TINs. Each TIN can be systematically

linked to an individual physician specialty code by us. Therefore, under this approach,

beneficiaries would be assigned to an ACO through a TIN based on the primary care

services they received from physicians billing under that TIN.

We also propose that ACO professionals within the respective TIN on which

beneficiary assignment is based, will be exclusive to one ACO agreement in the Shared

Savings Program. This exclusivity will only apply to the primary care physicians

(defined as physicians with a designation of internal medicine, geriatric medicine, family

practice, and general practice, as discussed in this rule) by whom beneficiary assignment

is established.

ACO participant TINs upon which beneficiary assignment is not dependent (for

example, acute care hospitals, surgical and medical specialties, RHCs, and FQHCs)

would be required to agree to participate in the ACO for the term of the 3-year

agreement, but would not be restricted to participation in a single ACO. As stated in

section II.G. of this proposed rule, competition in the marketplace promotes quality of

care for Medicare beneficiaries, protects access to a variety of providers, and helps

sustain the Medicare program by controlling cost pressures. All of these benefits to

Medicare patients would be reduced or eliminated if we allow the creation of ACOs with

significant market power. This is especially important in certain areas of the country that

might not have many specialists. In addition, exclusivity of ACO participant TINs upon

which beneficiary assignment is not dependent might also contribute to the prospects that

ACOs could develop excessive market power, especially in areas with shortages of

physicians. In turn, greater market power could provide opportunities for these

organizations to engage in activities that raise issues of fraud and abuse, such as those

related to self-referrals. For these reasons, physicians upon whom assignment is

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dependent would be committed for a 3-year period and be exclusive to one ACO.

Conversely, to ensure that physicians and other entities upon which assignment is not

dependent (that is, hospitals, FQHC, RHCs, specialists) can participate in more than one

ACO, and thereby facilitate the creation of competing ACOs, these providers and

suppliers would be committed to the 3-year agreement but would not be exclusive and

would have the flexibility to join another ACO.{jcomments off}