---
type: source
title: "Medicare ACOs In 2024: Increased Participation and Evolving Policy Impacts — Health Affairs"
author: "Health Affairs Forefront"
url: https://www.healthaffairs.org/do/10.1377/forefront.20251105.540959/
date: 2025-11-05
domain: health
secondary_domains: []
format: article
status: unprocessed
priority: medium
tags: [ACO, MSSP, Medicare, value-based-care, policy, downside-risk, 2024]
intake_tier: research-task
---

## Content

Health Affairs analysis of MSSP 2024 performance year results:

**Participation trends:**
- Increased ACO participation in 2024 (enrollment growing)
- Policy evolution: CMS 2026 rules restricting one-sided participation (reducing one-sided MSSP cap from 7 to 5 years starting 2027)
- New mandatory Ambulatory Specialty Model (ASM) for heart failure and low back pain

**Financial performance (from CMS data):**
- $2.48 billion net savings — record, 8th consecutive year
- $6.6 billion gross savings
- $641 per capita gross savings (up $128 from 2023)
- $241 per capita net savings (up $34 from 2023)
- Acceleration in per capita savings suggests quality improvement is compounding

**Risk distribution:**
- 2/3 of ACOs now in Level E or Enhanced (downside risk)
- Level E + Enhanced generated $5.4B of $6.6B gross savings (82%)
- The shift to downside risk is accelerating performance

**Quality metrics:**
- ACOs outperforming non-ACO peers on depression screening (53.5% vs 44.4%), BP control (71.2% vs 67.8%)
- Blood pressure, A1c control, cancer screening all improving
- NO quality-cost tradeoff observed — quality improving WITH cost reduction

**Policy context:**
- CMS 2026 "Transforming Episode Accountability Model" (TEAM) — new episode-based payment models
- Trump administration priorities: maximize ACO savings by pushing downside risk
- CMS Innovation Center refocusing on scalable APMs rather than new pilot programs

**Privia Health subsidiary data:**
- Privia ACOs: $233M+ total savings in 2024 performance year — 32% year-over-year increase

## Agent Notes

**Why this matters:** Provides detailed analysis framing around the headline $2.48B MSSP savings number. The Health Affairs framing is important: it's not just that VBC saves money, but that performance is accelerating and risk adoption is growing. The two-thirds of ACOs in downside risk is the structural shift — these are organizations BETTING on their ability to keep people healthy.

**What surprised me:** The acceleration in per capita savings ($34 more net, $128 more gross vs. 2023). If per capita savings are growing each year, the MSSP model is exhibiting learning curve effects — ACOs are getting better at VBC over time. This is the compounding dynamic that the KB's attractor state model predicts.

**What I expected but didn't find:** Evidence of ACO quality tradeoffs. The classic concern about capitated/at-risk models is they'll under-treat complex patients to avoid costs. The data shows the opposite — ACOs improve on depression screening, BP control, cancer screening at the same time they reduce costs. This is the aligned incentive model working as designed.

**KB connections:**
- Directly confirms [[the healthcare attractor state is a prevention-first system where aligned payment continuous monitoring and AI-augmented care delivery create a flywheel that profits from health rather than sickness]] — the ACO flywheel is empirically observable in 8-year data
- Confirms Belief 3: structural fix (VBC) is working, not just aspirational
- Connects to [[Devoted is the fastest-growing MA plan at 121 percent growth because purpose-built technology outperforms acquisition-based vertical integration during CMS tightening]] — the ACO data is the broader VBC evidence base that Devoted operates within

**Extraction hints:**
- ENRICHMENT: Enrich existing VBC transition claim with acceleration data — per capita savings are growing, 2/3 of ACOs in downside risk, quality improving alongside cost reduction
- CLAIM: "Medicare Shared Savings ACOs that moved to downside risk (Level E/Enhanced) generated 82% of total MSSP gross savings while representing two-thirds of participants — empirically demonstrating that aligned financial risk produces superior VBC performance to one-sided arrangements"
- NEW PRECISION: The quality-cost co-improvement data (depression screening up 9pp, BP control up 3pp while generating record savings) is the strongest counter to the "VBC under-treats to cut costs" concern

**Context:** Health Affairs Forefront, published November 2025. Leading health policy journal. Considered authoritative for VBC policy analysis.

## Curator Notes

PRIMARY CONNECTION: [[value-based care transitions stall at the payment boundary because 60 percent of payments touch value metrics but only 14 percent bear full risk]]
WHY ARCHIVED: Provides the qualitative framing and acceleration evidence missing from the raw CMS fact sheet. The "two-thirds in downside risk generating 82% of savings" is a specific claim candidate about risk-bearing ACOs as the high-performance tier.
EXTRACTION HINT: The risk stratification finding is the key insight — two-thirds of ACOs in downside risk generating 82% of savings creates a precise, claimable assertion about how financial risk shapes VBC performance.