§425.600. Selection of risk model.
42 C.F.R. § 425.600
(1) Level A. The ACO operates under a one-sided model as described under § 425.605(d)(1)(i).
(2) Level B. The ACO operates under a one-sided model as described under § 425.605(d)(1)(ii).
(3) Level C. The ACO operates under a two-sided model as described under § 425.605(d)(1)(iii).
(4) Level D. The ACO operates under a two-sided model as described under § 425.605(d)(1)(iv).
(5) Level E. The ACO operates under a two-sided model as described under § 425.605(d)(1)(v).
(ii) An ACO that previously participated in Track 1 under paragraph (a)(1) of this section or a new ACO identified as a re-entering ACO because more than 50 percent of its ACO participants have recent prior experience in a Track 1 ACO may elect to enter its agreement period at any of the levels of risk and potential reward available under paragraphs (a)(4)(i)(A)(2) through (5) of this section.
(2) Automatic advancement. Unless the ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i), the ACO is automatically advanced to the next level of the BASIC track's glide path at the start of each subsequent performance year of the agreement period, if a higher level of risk and potential reward is available under the BASIC track.
(i) Exception for ACO entering the BASIC track's glide path for an agreement period beginning on July 1, 2019. The automatic advancement does not apply at the start of the second performance year for an ACO entering the BASIC track's glide path for an agreement period beginning on July 1, 2019. For performance year 2020, the ACO remains in the same level of the BASIC track's glide path that it entered for the July 1, 2019 through December 31, 2019 performance year, unless the ACO chooses to advance more quickly in accordance with § 425.226(a)(2)(i). The ACO is automatically advanced to the next level of the BASIC track's glide path at the start of performance year 2021 and all subsequent performance years of the agreement period.
(ii) Exception for new legal entity identified as a low revenue ACO. An exception is available for a low revenue ACO that is a new legal entity and is not identified as a re-entering ACO that enters the BASIC track's glide path at Level A under paragraph (a)(4)(i)(A)(1) of this section, and is automatically advanced to Level B under paragraph (a)(4)(i)(A)(2) of this section for performance year 2 (or performance 3 in the case of ACOs entering an agreement period beginning on July 1, 2019). Prior to the automatic advancement of the ACO to Level C under paragraph (a)(4)(i)(A)(3) of this section, the ACO may elect to remain in Level B under paragraph (a)(4)(i)(A)(2) of this section for performance year 3 (performance year 4 in the case of ACOs entering an agreement period beginning on July 1, 2019). In the case of an ACO that elects to remain in Level B for an additional performance year pursuant to the second sentence of paragraph (a)(4)(i)(B)(2)(ii) of this section, and except as provided in paragraph (a)(4)(i)(B)(2)(vi) of this section, the ACO is automatically advanced to Level E under paragraph (a)(4)(i)(A)(5) of this section at the start of performance year 4 (or performance year 5 in the case of ACOs entering an agreement period beginning on July 1, 2019).
(iii) Exception for ACOs participating in the BASIC track's glide path that elect to maintain their participation level for performance year 2021. Prior to the automatic advancement for performance year 2021, an ACO that is participating in the BASIC track's glide path for performance year 2020 may elect to remain in the same level of the BASIC track's glide path that it entered for the 2020 performance year, for performance year 2021. For performance year 2022, the ACO is automatically advanced to the level of the BASIC track's glide path to which the ACO would have automatically advanced absent the election to maintain its participation level for performance year 2021, unless the ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i). A voluntary election by an ACO under this paragraph must be made in the form and manner and by a deadline established by CMS.
(iv) Exception for ACOs participating in the BASIC track's glide path that elect to maintain their participation level for performance year 2022. Prior to the automatic advancement for performance year 2022, an ACO that is participating in the BASIC track's glide path for performance year 2021 may elect to remain in the same level of the BASIC track's glide path in which it participated during the 2021 performance year, for performance year 2022. Except as provided in paragraph (a)(4)(i)(B)(2)(vi) of this section, for performance year 2023, the ACO is automatically advanced to the level of the BASIC track's glide path to which the ACO would have automatically advanced absent the election to maintain its participation level for performance year 2022 and, if applicable, the election to maintain its participation level for performance year 2021 under paragraph (a)(4)(i)(B)(2)(iii) of this section, unless the ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i). A voluntary election by an ACO under this paragraph must be made in the form and manner and by a deadline established by CMS.
(v) Prior to entering performance-based risk, an ACO must meet all requirements to participate under performance-based risk, including establishing an adequate repayment mechanism as specified under § 425.204(f) and selecting a MSR/MLR from the options specified under § 425.605(b).
(vi) For performance year 2023, an ACO in Level A under paragraph (a)(4)(i)(A)(1) of this section or in Level B under paragraph (a)(4)(i)(A)(2) of this section may elect to remain in the same level of the BASIC track's glide path in which it participated during performance year 2022, for the remainder of the agreement period, unless the ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i). If the ACO does not elect to remain under Level A or Level B, for performance year 2023, the ACO is automatically advanced to the next level of the BASIC track's glide path to which the ACO would have automatically advanced absent any election to maintain its participation level for performance year 2022 under paragraph (a)(4)(i)(B)(2)(iv) of this section and, if applicable, the election to maintain its participation level for performance year 2021 under paragraph (a)(4)(i)(B)(2)(iii) of this section, unless the ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i). A voluntary election by an ACO under this paragraph must be made in the form and manner and by a deadline established by CMS.
(vii) For performance year 2024, an ACO with an agreement period beginning January 1, 2023 in Level A under paragraph (a)(4)(i)(A)(1) of this section or in Level B under paragraph (a)(4)(i)(A)(2) of this section may elect to remain in the same level of the BASIC track's glide path in which it participated during performance year 2023, for the remainder of the agreement period, unless the ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i). If the ACO does not elect to remain under Level A or Level B, for performance year 2024, the ACO is automatically advanced to the next level of the BASIC track's glide path, unless the ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i). A voluntary election by an ACO under this paragraph must be made in the form and manner and by a deadline established by CMS.
(3) If the ACO fails to meet the requirements to participate under performance-based risk under paragraph (a)(4)(i)(B)(2)(v) of this section, the agreement is terminated.
(4) If, in accordance with § 425.226(a)(2)(i), the ACO elects to transition to a higher level of risk and reward available under paragraphs (a)(4)(i)(A)(3) through (5) of this section, then the automatic transition to levels of higher risk and reward specified in paragraph (a)(4)(i)(B)(2) of this section applies to all subsequent performance years of the agreement period.
(2) Automatic advancement. An ACO is automatically advanced to the next level of the BASIC track's glide path at the start of each subsequent performance year of the agreement period, if a higher level of risk and potential reward is available under the BASIC track, except as follows:
(i) The ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i).
(ii) The ACO elects to maintain its level of participation as provided in paragraph (a)(4)(i)(C)(3) of this section.
(iii) The ACO is automatically advanced to Level E pursuant to paragraph paragraph (i)(2)(i) of this section.
(3) Election to remain under a one-sided model. An eligible ACO that enters the BASIC track's glide path at Level A under paragraph (a)(4)(i)(A)(1) of this section and is currently at Level A may elect to remain in Level A under paragraph (a)(4)(i)(A)(1) of this section for all subsequent performance years of the agreement period.
(i) To be eligible to participate under Level A of the BASIC track as described in this paragraph, the ACO must meet the following requirements: the ACO is participating in its first agreement period under the BASIC track under paragraph (a)(4) of this section, and is not participating in an agreement period under the BASIC track as a renewing ACO (as defined at § 425.20) or a re-entering ACO (as defined in § 425.20) that previously participated in the BASIC track's glide path under paragraph (a)(4) of this section; and the ACO is inexperienced with performance-based risk Medicare ACO initiatives (as defined in § 425.20).
(ii) A voluntary election by an ACO under this paragraph (a)(4)(i)(C)(3) must be made in the form and manner and by a deadline established by CMS.
(iii) The ACO's election to remain in Level A applies for the entirety of the agreement period, unless the ACO elects to transition to a higher level of risk and potential reward within the BASIC track's glide path as provided in § 425.226(a)(2)(i).
(4) Prior to entering performance-based risk, an ACO must meet all requirements to participate under performance-based risk, including establishing an adequate repayment mechanism as specified under § 425.204(f) and selecting a MSR/MLR from the options specified under § 425.605(b).
(5) If the ACO fails to meet the requirements to participate under performance-based risk under paragraph (a)(4)(i)(C)(4) of this section, the agreement is terminated.
(6) If, in accordance with § 425.226(a)(2)(i), the ACO elects to transition to a higher level of risk and reward available under paragraphs (a)(4)(i)(A)(3) through (5) of this section, then the automatic transition to levels of higher risk and reward specified in paragraph (a)(4)(i)(C)(2) of this section applies to all subsequent performance years of the agreement period.
Notes, amendments, and revision history
Amendments
[76 FR 67973, Nov. 2, 2011, as amended at 80 FR 32841, June 9, 2015; 83 FR 68069, Dec. 31, 2018; 85 FR 27625, May 8, 2020; 85 FR 85041, Dec. 28, 2020; 86 FR 45521, Aug. 13, 2021; 87 FR 70235, Nov. 18, 2022; 88 FR 79547, Nov. 16, 2023; 90 FR 50017, Nov. 5, 2025]
Authority
Authority: 42 U.S.C. 1302, 1306, 1395hh, and 1395jjj.
Source
Source: 76 FR 67973, Nov. 2, 2011, unless otherwise noted.
Amendments
[76 FR 67973, Nov. 2, 2011, as amended at 80 FR 32841, June 9, 2015; 83 FR 68069, Dec. 31, 2018; 85 FR 27625, May 8, 2020; 85 FR 85041, Dec. 28, 2020; 86 FR 45521, Aug. 13, 2021; 87 FR 70235, Nov. 18, 2022; 88 FR 79547, Nov. 16, 2023; 90 FR 50017, Nov. 5, 2025]