42 CFR §425.306

1. (a)Each ACO participant must commit to the term of the participation agreement and sign an ACO participant agreement that complies with the requirements of this part.
2. (b)
   1. (1)Except as specified in paragraph (b)(2) of this section, ACO participants are not required to be exclusive to one Shared Savings Program ACO.
   2. (2)Each ACO participant that submits claims for services used to determine the ACO's assigned population under subpart E of this part must be exclusive to one Shared Savings Program ACO. If, during a benchmark or performance year (including the 3-month claims runout for such benchmark or performance year), an ACO participant that participates in more than one ACO submits claims for services used in assignment under subpart E of this part, then:
      1. (i)CMS will not consider any services billed through the TIN of the ACO participant when performing assignment under subpart E of this part for the benchmark or performance year.
      2. (ii)The ACO may be subject to the pre-termination actions set forth in § 425.216, termination under § 425.218, or both.