Employer Use of Big Three PBMs Falls to 54% in 2026
Employer contracts with the Big Three PBMs dropped nearly 10 points in a single year — and over half are considering leaving entirely.
Employer contracting with the “Big Three” PBMs — CVS Caremark, Express Scripts, and Optum Rx — fell from 63.4% in 2025 to 54.3% in 2026, according to the National Alliance of Healthcare Purchaser Coalitions’ annual Pulse of the Purchaser survey of 408 employers. The shift is driven largely by employers with fewer than 1,000 employees, but the pressure extends well beyond small business.
The Numbers Behind the Shift
Among employers still contracted with the Big Three, 55.7% say they’re considering a PBM change within the next one to three years, compared with just 31.1% of employers already using alternative PBMs. Notably, the largest employers — those with 10,000-plus employees — are the slowest to actually move, but show the greatest stated interest in switching going forward. Nearly one in four Big Three clients (23.4%) admitted they aren’t sure what’s actually in their PBM contract, roughly double the rate among employers using alternative PBMs.
What’s Driving the Move
Common transparency features employers are seeking include 100% rebate pass-through, access to claims-level pharmacy data, disclosed administrative fees, and full audit rights including rebate audits. This tracks with a broader pattern: transparent PBM adoption climbed from 12% to 31% in a single year in the 2025 Pulse survey, and was linked to lower reported premiums among adopters.
What This Means for Access & Formulary Teams
Contract literacy is now a competitive differentiator. With nearly a quarter of Big Three clients unsure what’s in their own contracts, plan sponsors that can clearly articulate rebate terms, fees, and audit rights to manufacturers and stakeholders hold a real negotiating advantage.
Large employer inertia won’t last. The gap between large employers’ stated switching interest and actual movement suggests a wave of large-account PBM transitions may be building — manufacturers and specialty pharmacies should model contract disruption scenarios now.
Claims data access correlates with better cost management. Employers with full claims data visibility are deploying meaningfully more cost-containment strategies — a signal that data transparency, not just price, is becoming the core PBM selection criterion.
FAQ
What percentage of employers now use the Big Three PBMs?
54.3% of employers surveyed in 2026 contract with CVS Caremark, Express Scripts, or Optum Rx, down from 63.4% in 2025.
Why are employers switching away from the Big Three?
Employers cite a desire for greater transparency, including 100% rebate pass-through, claims-level data access, disclosed fees, and full audit rights — features more commonly offered by alternative PBMs.
Which employers are most likely to switch PBMs?
Smaller employers, particularly those under 1,000 employees, have driven most of the actual switching so far, while larger employers (10,000-plus) show high interest in switching but have been slower to act.
Sources
- National Alliance of Healthcare Purchaser Coalitions, Employers with Claims Data Access Take More Action on Healthcare Costs
- AJMC, Employers With Claims Data Access Take More Cost Action, Survey Finds
- NCPA, Employers Switching Away from Big Three PBMs, Pushing for Fairer Terms