Section 425.601 - Establishing, adjusting, and updating the benchmark for agreement periods beginning on or after July 1, 2019, and before January 1, 2024(a)Computing per capita Medicare Part A and Part B benchmark expenditures for an ACO's first agreement period. For agreement periods beginning on July 1, 2019, and in subsequent years, in computing an ACO's historical benchmark for its first agreement period under the Shared Savings Program, CMS determines the per capita Parts A and B fee-for-service expenditures for beneficiaries that would have been assigned to the ACO in any of the 3 most recent years prior to the start of the agreement period using the ACO participant TINs identified before the start of the agreement period as required under § 425.118(a) and the beneficiary assignment methodology selected by the ACO for the first performance year of the agreement period as required under § 425.400(a)(4)(ii) . CMS does all of the following: (1) Calculates the payment amounts included in Parts A and B fee-for-service claims using a 3-month claims run out with a completion factor. (i) This calculation excludes indirect medical education (IME) and disproportionate share hospital (DSH) payments, and the supplemental payment for IHS/Tribal hospitals and Puerto Rico hospitals.(ii) This calculation includes individually beneficiary identifiable final payments made under a demonstration, pilot or time limited program.(2) Makes separate expenditure calculations for each of the following populations of beneficiaries: ESRD, disabled, aged/dual eligible Medicare and Medicaid beneficiaries and aged/non-dual eligible Medicare and Medicaid beneficiaries.(3) Adjusts expenditures for changes in severity and case mix using prospective HCC risk scores.(4) Truncates an assigned beneficiary's total annual Parts A and B fee-for-service per capita expenditures at the 99th percentile of national Medicare fee-for-service expenditures for assignable beneficiaries identified for the 12-month calendar year corresponding to each benchmark year in order to minimize variation from catastrophically large claims.(5) Trends forward expenditures for each benchmark year (BY1 and BY2) to the third benchmark year (BY3) dollars using a blend of national and regional growth rates. (i) To trend forward the benchmark, CMS makes separate calculations for expenditure categories for each of the following populations of beneficiaries:(C) Aged/dual eligible Medicare and Medicaid beneficiaries.(D) Aged/non-dual eligible Medicare and Medicaid beneficiaries.(ii) National growth rates are computed using CMS Office of the Actuary national Medicare expenditure data for each of the years making up the historical benchmark for assignable beneficiaries identified for the 12-month calendar year corresponding to each benchmark year.(iii) Regional growth rates are computed using expenditures for the ACO's regional service area for each of the years making up the historical benchmark as follows: (A) Determine the counties included in the ACO's regional service area based on the ACO's assigned beneficiary population for the relevant benchmark year.(B) Determine the ACO's regional expenditures as specified under paragraphs (c) and (d) of this section.(iv) The national and regional growth rates are blended together by taking a weighted average of the two. The weight applied to the- (A) National growth rate is calculated as the share of assignable beneficiaries in the ACO's regional service area for BY3 that are assigned to the ACO in BY3, as calculated in paragraph (a)(5)(v) of this section; and(B) Regional growth rate is equal to 1 minus the weight applied to the national growth rate.(v) CMS calculates the share of assignable beneficiaries in the ACO's regional service area that are assigned to the ACO by doing all of the following: (A) Calculating the county-level share of assignable beneficiaries that are assigned to the ACO for each county in the ACO's regional service area.(B) Weighting the county-level shares according to the ACO's proportion of assigned beneficiaries in the county, determined by the number of the ACO's assigned beneficiaries residing in the county in relation to the ACO's total number of assigned beneficiaries.(C) Aggregating the weighted county-level shares for all counties in the ACO's regional service area.(6) Restates BY1 and BY2 trended and risk adjusted expenditures using BY3 proportions of ESRD, disabled, aged/dual eligible Medicare and Medicaid beneficiaries and aged/non-dual eligible Medicare and Medicaid beneficiaries.(7) Weights each year of the benchmark for an ACO's initial agreement period using the following percentages: (8) Adjusts the historical benchmark based on the ACO's regional service area expenditures, making separate calculations for the following populations of beneficiaries: ESRD, disabled, aged/dual eligible Medicare and Medicaid beneficiaries, and aged/non-dual eligible Medicare and Medicaid beneficiaries. CMS does all of the following: (i) Calculates an average per capita amount of expenditures for the ACO's regional service area as follows: (A) Determines the counties included in the ACO's regional service area based on the ACO's BY3 assigned beneficiary population.(B) Determines the ACO's regional expenditures as specified under paragraphs (c) and (d) of this section for BY3.(C) Adjusts for differences in severity and case mix between the ACO's assigned beneficiary population and the assignable beneficiary population for the ACO's regional service area identified for the 12-month calendar year that corresponds to BY3.(ii) Calculates the adjustment as follows:(A) Determines the difference between the average per capita amount of expenditures for the ACO's regional service area as specified under paragraph (a)(8)(i) of this section and the average per capita amount of the ACO's historical benchmark determined under paragraphs (a)(1) through (7) of this section, for each of the following populations of beneficiaries:(3) Aged/dual eligible for Medicare and Medicaid.(4) Aged/non-dual eligible for Medicare and Medicaid.(B) Applies a percentage, as determined in paragraph (f) of this section.(C) Caps the per capita dollar amount for each Medicare enrollment type (ESRD, Disabled, Aged/dual eligible Medicare and Medicaid beneficiaries, Aged/non-dual eligible Medicare and Medicaid beneficiaries) calculated under paragraph (a)(8)(ii)(B) of this section at a dollar amount equal to 5 percent of national per capita expenditures for Parts A and B services under the original Medicare fee-for-service program in BY3 for assignable beneficiaries in that enrollment type identified for the 12-month calendar year corresponding to BY3 using data from the CMS Office of the Actuary.(1) For positive adjustments, the per capita dollar amount for a Medicare enrollment type is capped at 5 percent of the national per capita expenditure amount for the enrollment type for BY3.(2) For negative adjustments, the per capita dollar amount for a Medicare enrollment type is capped at negative 5 percent of the national per capita expenditure amount for the enrollment type for BY3.(9) For the second and each subsequent performance year during the term of the agreement period, the ACO's benchmark is adjusted for the following, as applicable: For the addition and removal of ACO participants or ACO providers/suppliers in accordance with § 425.118(b) , for a change to the ACO's beneficiary assignment methodology selection under § 425.226(a)(1) , and for a change to the beneficiary assignment methodology specified in subpart E of this part. To adjust the benchmark, CMS does the following: (i) Takes into account the expenditures of beneficiaries who would have been assigned to the ACO in any of the 3 most recent years prior to the start of the agreement period.(ii) Redetermines the regional adjustment amount under paragraph (a)(8) of this section, according to the ACO's assigned beneficiaries for BY3.(10) The historical benchmark is further adjusted at the time of reconciliation for a performance year to account for changes in severity and case mix of the ACO's assigned beneficiary population as described under §§ 425.605(a) , 425.609(c) , and 425.610(a) .(b)Updating the benchmark. For all agreement periods beginning on July 1, 2019, and in subsequent years, CMS updates the historical benchmark annually for each year of the agreement period using a blend of national and regional growth rates. (1) To update the benchmark, CMS makes separate calculations for expenditure categories for each of the following populations of beneficiaries: (iii) Aged/dual eligible Medicare and Medicaid beneficiaries.(iv) Aged/non-dual eligible Medicare and Medicaid beneficiaries.(2) National growth rates are computed using CMS Office of the Actuary national Medicare expenditure data for BY3 and the performance year for assignable beneficiaries identified for the 12-month calendar year corresponding to each year.(3) Regional growth rates are computed using expenditures for the ACO's regional service area for BY3 and the performance year, computed as follows:(i) Determine the counties included in the ACO's regional service area based on the ACO's assigned beneficiary population for the year.(ii) Determine the ACO's regional expenditures as specified under paragraphs (c) and (d) of this section.(4) The national and regional growth rates are blended together by taking a weighted average of the two. The weight applied to the-(i) National growth rate is calculated as the share of assignable beneficiaries in the ACO's regional service area that are assigned to the ACO for the applicable performance year as specified in paragraph (a)(5)(v) of this section; and(ii) Regional growth rate is equal to 1 minus the weight applied to the national growth rate.(c)Calculating county expenditures. For all agreement periods beginning on July 1, 2019, and in subsequent years, CMS does all of the following to determine risk adjusted county fee-for-service expenditures for use in calculating the ACO's regional fee-for-service expenditures: (1)(i) Determines average county fee-for-service expenditures based on expenditures for the assignable population of beneficiaries in each county in the ACO's regional service area, where assignable beneficiaries are identified for the 12-month calendar year corresponding to the relevant benchmark or performance year.(ii) Makes separate expenditure calculations for each of the following populations of beneficiaries:(C) Aged/dual eligible Medicare and Medicaid beneficiaries.(D) Aged/non-dual eligible Medicare and Medicaid beneficiaries.(2) Calculates assignable beneficiary expenditures using the payment amounts included in Parts A and B fee-for-service claims with dates of service in the 12-month calendar year for the relevant benchmark or performance year, using a 3-month claims run out with a completion factor. The calculation-(i) Excludes IME and DSH payments, and the supplemental payment for IHS/Tribal hospitals and Puerto Rico hospitals; and(ii) Considers individually beneficiary identifiable final payments made under a demonstration, pilot or time limited program.(3) Truncates a beneficiary's total annual Parts A and B fee-for-service per capita expenditures at the 99th percentile of national Medicare fee-for-service expenditures for assignable beneficiaries identified for the 12-month calendar year that corresponds to the relevant benchmark or performance year, in order to minimize variation from catastrophically large claims.(4) Adjusts fee-for-service expenditures for severity and case mix of assignable beneficiaries in the county using prospective HCC risk scores. The calculation is made according to the following populations of beneficiaries:(iii) Aged/dual eligible Medicare and Medicaid beneficiaries.(iv) Aged/non-dual eligible Medicare and Medicaid beneficiaries.(d)Calculating regional expenditures. For all agreement periods beginning on July 1, 2019, and in subsequent years, CMS calculates an ACO's risk adjusted regional expenditures by:(1) Weighting the risk-adjusted county-level fee-for-service expenditures determined under paragraph (c) of this section according to the ACO's proportion of assigned beneficiaries in the county, determined by the number of the ACO's assigned beneficiaries in the applicable population (according to Medicare enrollment type) residing in the county in relation to the ACO's total number of assigned beneficiaries in the applicable population (according to Medicare enrollment type) for the relevant benchmark or performance year for each of the following populations of beneficiaries:(iii) Aged/dual eligible Medicare and Medicaid beneficiaries.(iv) Aged/non-dual eligible Medicare and Medicaid beneficiaries.(2) Aggregating the values determined under paragraph (d)(1) of this section for each population of beneficiaries (according to Medicare enrollment type) across all counties within the ACO's regional service area.(e)Resetting the benchmark.(1) An ACO's benchmark is reset at the start of each subsequent agreement period.(2) For second or subsequent agreements periods beginning on July 1, 2019, and in subsequent years, CMS establishes, adjusts, and updates the rebased historical benchmark in accordance with paragraphs (a) through (d) of this section with the following modifications:(i) Rather than weighting each year of the benchmark using the percentages provided in paragraph (a)(7) of this section, each benchmark year is weighted equally.(ii) For a renewing ACO or re-entering ACO whose prior agreement period benchmark was calculated according to § 425.603(c) , to determine the weight used in the regional adjustment calculation described in paragraph (f) of this section, CMS considers the agreement period the ACO is entering into according to § 425.600(f) in combination with either of the following-(A) The weight previously applied to calculate the regional adjustment to the ACO's benchmark under § 425.603(c)(9) in its most recent prior agreement period; or(B) For a new ACO identified as a re-entering ACO, CMS considers the weight previously applied to calculate the regional adjustment to the benchmark under § 425.603(c)(9) in its most recent prior agreement period of the ACO in which the majority of the new ACO's participants were participating previously.(f)Phase-in of weights used in regional adjustment calculation.(1) The first time that an ACO's benchmark is adjusted based on the ACO's regional service area expenditures, CMS calculates the regional adjustment as follows: (i) Using 35 percent of the difference between the average per capita amount of expenditures for the ACO's regional service area and the average per capita amount of the ACO's initial or rebased historical benchmark, if the ACO is determined to have lower spending than the ACO's regional service area.(ii) Using 15 percent of the difference between the average per capita amount of expenditures for the ACO's regional service area and the average per capita amount of the ACO's initial or rebased historical benchmark, if the ACO is determined to have higher spending than the ACO's regional service area.(2) The second time that an ACO's benchmark is adjusted based on the ACO's regional service area expenditures, CMS calculates the regional adjustment as follows: (i) Using 50 percent of the difference between the average per capita amount of expenditures for the ACO's regional service area and the average per capita amount of the ACO's rebased historical benchmark if the ACO is determined to have lower spending than the ACO's regional service area.(ii) Using 25 percent of the difference between the average per capita amount of expenditures for the ACO's regional service area and the average per capita amount of the ACO's rebased historical benchmark if the ACO is determined to have higher spending than the ACO's regional service area.(3) The third time that an ACO's benchmark is adjusted based on the ACO's regional service area expenditures, CMS calculates the regional adjustment as follows:(i) Using 50 percent of the difference between the average per capita amount of expenditures for the ACO's regional service area and the average per capita amount of the ACO's rebased historical benchmark if the ACO is determined to have lower spending than the ACO's regional service area.(ii) Using 35 percent of the difference between the average per capita amount of expenditures for the ACO's regional service area and the average per capita amount of the ACO's rebased historical benchmark if the ACO is determined to have higher spending than the ACO's regional service area.(4) The fourth or subsequent time that an ACO's benchmark is adjusted based on the ACO's regional service area expenditures, CMS calculates the regional adjustment to the historical benchmark using 50 percent of the difference between the average per capita amount of expenditures for the ACO's regional service area and the average per capita amount of the ACO's rebased historical benchmark.(5) To determine if an ACO has lower or higher spending compared to the ACO's regional service area, CMS does the following:(i) Multiplies the difference between the average per capita amount of expenditures for the ACO's regional service area and the average per capita amount of the ACO's historical benchmark for each population of beneficiaries (ESRD, Disabled, Aged/dual eligible Medicare and Medicaid beneficiaries, Aged/non-dual eligible Medicare and Medicaid beneficiaries) as calculated under either paragraph (a)(8)(ii)(A) or (e) of this section by the applicable proportion of the ACO's assigned beneficiary population (ESRD, Disabled, Aged/dual eligible Medicare and Medicaid beneficiaries, Aged/non-dual eligible Medicare and Medicaid beneficiaries) for BY3 of the historical benchmark.(ii) Sums the amounts determined in paragraph (f)(5)(i) of this section across the populations of beneficiaries (ESRD, Disabled, Aged/dual eligible Medicare and Medicaid beneficiaries, Aged/non-dual eligible Medicare and Medicaid beneficiaries).(iii) If the resulting sum is a net positive value, the ACO is considered to have lower spending compared to the ACO's regional service area. If the resulting sum is a net negative value, the ACO is considered to have higher spending compared to the ACO's regional service area.(iv) If during the term of the agreement period CMS adjusts the ACO's benchmark, as specified in paragraph (a)(9) of this section, CMS redetermines whether the ACO is considered to have lower spending or higher spending compared to the ACO's regional service area for purposes of determining the percentage in paragraphs (f)(1) through (3) of this section used in calculating the adjustment under either paragraph (a)(8) or (e) of this section.(g)July 1, 2019 through December 31, 2019 performance year. In determining performance for the July 1, 2019 through December 31, 2019 performance year described in § 425.609(c) , CMS does all of the following:(1) When adjusting the benchmark using the methodology set forth in paragraph (a)(10) of this section and § 425.609(c) , CMS adjusts for severity and case mix between BY3 and CY 2019.(2) When updating the benchmark using the methodology set forth in paragraph (b) of this section and § 425.609(c) , CMS updates the benchmark based on growth between BY3 and CY 2019.83 FR 68071, Dec. 31, 2018, as amended at 85 FR 85042, Dec. 28, 2020; 87 FR 70237, Nov. 18, 2022; 88 FR 79547, Nov. 16, 2023 83 FR 68071, 12/31/2018; 85 FR 85042, 1/1/2021; 87 FR 70237, 1/1/2023; 88 FR 79547, 1/1/2024