; and (3) require that any regional contributions or expenditures (below the national level) used directly or indirectly to establish, update, or adjust benchmark expenditures be calculated in a manner that excludes the expenditure impact of ACOs in the applicable region, including any regional expenditures associated with Medicare fee-for-service beneficiaries assigned to such ACOs. (c) Shared savings option Prior to the beginning of the first performance year (as defined for purposes of subsection (a)) that begins after the date of the enactment of this Act, and notwithstanding any other provision of law, the Secretary of Health and Human Services shall establish a voluntary full-risk option under the Medicare Shared Savings Program (as described in section 1899 of the Social Security Act ( 42 U.S.C. 1395jjj )) under which the percent of shared savings paid to an ACO under section 1899(d)(2) of the Social Security Act ( 42 U.S.C. 1395jjj(d)(2) ) shall be set at 100 percent, with the ACO bearing commensurate risk of any shared losses. (d) Report Not later than 90 days after the date of enactment of this Act, the Administrator of the Centers for Medicare & Medicaid Services shall submit to the appropriate committees of Congress a report on mechanisms that the agency can take to avoid penalizing ACOs for achieving cost savings and account for regional variations in spending in a manner that prevents arbitrary Medicare Shared Savings Program outcomes for ACOs. Such report shall include specific actions that the Centers for Medicare & Medicaid Services can take to develop and implement effective benchmarks and guardrails for any changes made to the agency’s benchmarking policies. 3. Advanced payment model incentive, participation, and threshold modifications (a) In general Section 1833(z) of the Social Security Act ( 42 U.S.C. 1395l(z) ) is amended— (1) in paragraph (1)(A)— (A) by striking with 2025 and inserting with 2027