The Top Pharmacy Benefit Managers of 2025: Market Share and Key Industry Developments

Three is still the magic number for pharmacy benefit managers (PBMs).

For 2025, 80% of all equivalent prescription claims were processed by three companies: the CVS Caremark business of CVS Health, the Express Scripts business of Cigna, and the Optum Rx business of UnitedHealth Group. Express Scripts continued to pull ahead of its peers, while CVS Caremark’s claim volume declined for the second year.

Independent PBMs continued to gain business from these larger PBMs, showing fragmentation at the margins. Many smaller PBMs still rely on their larger competitors for claims processing, network management, and rebate negotiation. So even if a plan sponsor chooses an alternative PBM, the Big Three can still win with behind-the scenes economics.

Below, we draw on DCI's new 2026 Economic Report on U.S. Pharmacies and Pharmacy Benefit Managers to break down the latest market share data for the largest companies.

The Big Three PBMs’ dominance persists, but they face growing regulatory and competitive constraints. The largest PBMs are restructuring their businesses in response to client demands, legislative changes, and legal pressures. The emerging Net Pricing Drug Channel will accelerate these shifts, forcing changes in how PBMs generate profits, structure contracts, and justify their role in the drug channel.

PBM Industry Update 2026: Trends, Challenges, and What's Ahead.

For a deeper dive into the state of the industry, register for DCI’s next webinar on April 10, 2026, from 12:00 p.m. to 1:30 p.m. ET. Adam J. Fein and Bryce Platt will unpack the good, the bad, and the ugly of the PBM industry—and explore what it means for you. Click here to learn more and sign up.

2025’S BIG PBM NUMBERS

DCI estimates that for 2025, 80% of all equivalent prescription claims were processed by three companies: the Caremark business of CVS Health, the Express Scripts business of Cigna, and the Optum Rx business of UnitedHealth Group. This share was consistent with the large PBMs’ aggregate share for the past few years. This level of concentration remains extraordinarily high—and remarkably stable—given the policy and competitive noise surrounding the industry.

Note that the 80% figure refers to prescription claims processed, not to the number of covered lives handled via rebate negotiations. That distinction is frequently misunderstood, because rebate aggregation (discussed below) creates the illusion of even greater scale. These data appear in Chapter 5 of our new 2026 Economic Report on U.S. Pharmacies and Pharmacy Benefit Managers.

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Here are recent marketplace developments for some of the largest companies:

• Express Scripts (Cigna). The Express Scripts business is reported within the Evernorth Health Services segment in Cigna’s financial reports. Evernorth also operates myMatrixx, a PBM focused on workers’ compensation.
  
  Express Scripts claimed the top spot for the second consecutive year. Express Scripts’ total adjusted prescription claims volume grew by 4.8%, from 2.12 billion in 2024 to 2.22 billion in 2025. (See Exhibit 114 in our new pharmacy/PBM report.) This growth reflects both organic expansion and the continued consolidation of large client relationships.
  
  Its climb to the top of the PBM heap came from multiple sources, including:
  • Cigna’s PBM business shifted from Optum Rx to Express Scripts after the Cigna–Express Scripts combination
  • Express Scripts’ multifaceted strategic relationship with Prime Therapeutics, which now relies on Express Scripts for nearly half of its overall network spend
  • Centene’s 2024 shift from CVS Caremark to Express Scripts
  • TRICARE, which in 2024 began requiring its beneficiaries to use Express Scripts’ Accredo specialty pharmacy or a military pharmacy to fill prescriptions for certain specialty maintenance drugs
  
  The downside of Express Scripts’ growth and customer concentration showed up last year, when Cigna reported profit pressures after it “proactively improved the economic terms of the contracts for the benefit of these long-term strategic clients.” Translation: Centene and Prime Therapeutics got better deals in exchange for their volume.

• CVS Caremark (CVS Health). The PBM business is part of CVS Health’s Health Services segment, which includes CVS Caremark, Cordavis, Oak Street Health, Signify Health, and MinuteClinic.
  
  For 2025, total PBM 30-day equivalent claims processed fell by 0.9%, to 1.9 billion. CVS Caremark’s claims volume peaked in 2023 at 2.3 billion, prior to the transition of Centene’s PBM business to Express Scripts in January 2024.
  
  For 2026, Caremark should get a boost because it replaced Optum Rx as the PBM for the California Public Employees' Retirement System (CalPERS).
  
  CVS Health has provided certain PBM services to Elevance Health’s CarelonRx business, including such PBM administrative functions as claims processing and prescription fulfillment services. Such behind-the-scenes service relationships further blur the lines between competitors and collaborators. In 2024, the CVS agreement was extended for an additional three years, through 2027. Elevance has the option to extend for an additional three-year term under the same terms and conditions.

• Optum Rx (UnitedHealth Group). UnitedHealth Group became the third-largest PBM when it began using its internal Optum Rx PBM subsidiary for its commercial PBM business.
  
  For 2025, it managed $188 billion in drug spend, of which $87 billion (46%) was classified by Optum Rx as specialty pharmaceuticals. Equivalent claims at Optum Rx grew by 36 million (+2.2%), from 1.623 billion in 2024 to 1.659 billion in 2025.
  
  Optum Rx’s largest customer is UnitedHealthcare, UnitedHealth Group’s health insurance business. For 2025, internal UnitedHealth Group businesses account for 63% of Optum Rx’s revenues. That’s a structural advantage that allows Optum Rx to maintain its position in a way that competitors cannot easily replicate. The remainder comes from unaffiliated commercial health plans, employers, and Medicaid programs.

• Prime Therapeutics. Prime operates as a pass-through PBM for 23 Blue Cross and Blue Shield health plans and the subsidiaries and affiliates of those plans. Nineteen of these plans collectively own the business. Prime also provides PBM services for more than two million lives through non-Blues health plans and self-funded employer groups.
  
  For 2025, Prime reported $55.3 billion in prescription spending and 407 million claims, compared with 2024 figures of $52.7 billion in spending and 411 million claims. These figures include only full-service PBM services and exclude claims from medical specialty and state government solutions. Due to Prime’s relationship with Express Scripts, about half of its prescription claims are included with the Express Scripts figures shown above.
  
  In 2022, Prime Therapeutics completed its acquisition of Magellan Rx from Centene. In 2024, Prime Therapeutics invested $115 million in JUDI Health (then known as Capital Rx) and announced an agreement to use JUDI as its adjudication platform.
  
  In 2020, Express Scripts took over retail pharmacy network contracting for a portion of Prime Therapeutics’ business. Prime acquired Magellan Rx in 2022, so Express Scripts network claims increased further as that business was transitioned during 2023. For 2024, we estimate that Express Scripts handled pharmacy network contracting for about half of Prime’s overall network spend. Consequently, we include these claims in the figures shown above.

For more details on other PBMs, see Chapter 5 of our new pharmacy/PBM report:

• Section 5.2.2. provides further details about the largest three PBMs as well information about Centene Pharmacy Services, Elevance Health’s CarelonRx business, Humana, and MedImpact Healthcare Systems.

• Section 5.2.3. profiles 18 smaller PBMs that are privately held independent businesses or owned by retail chains and health systems.

• Section 5.2.4. examines PBM-affiliated group purchasing organizations.

• Section 5.2.5. reviews the private label businesses that are subsidiaries of the same parent companies that operate the largest three PBMs.

BEHIND THE NUMBERS

There are several important considerations when reviewing the figures above:

• Rebate Aggregation. The figures above do not correspond to the number of covered lives handled via rebate negotiations.
  
  Many smaller PBMs do not have the scale to negotiate favorable formulary rebates and may lack a claims processing system. In these situations, a larger PBM acts as an aggregator for these smaller entities. The bigger PBM submits a larger consolidated rebate invoice, and the smaller player gains access to better pricing and a national claims system.
  
  Rebate aggregation also occurs via the large PBMs’ group purchasing organizations, which handle rebate negotiations with manufacturers and provide other services to manufacturers and the groups’ members. To date, these groups are focused on commercial, nongovernmental business. The three major PBM-owned purchasing groups include:
  • Ascent Health Solutions, which is jointly owned by Cigna Spruce Holdings GmbH (a wholly subsidiary of Cigna), Kroger, and Prime Therapeutics.
  • Emisar Pharma Services, which is part of UnitedHealth Group’s Optum business.
  • Zinc Health Services, a U.S.-based contracting entity formed by CVS Health. Elevance Health reportedly owns a minority interest in Zinc.
  There are also smaller PBM-affiliated GPOs.
  
  We profile these GPOs in Section 5.2.4. of our new pharmacy/PBM report.
  
  Due to this aggregation, there is substantial double-counting when evaluating covered lives. Summing up the figures reported by individual PBMs results in an aggregate number of lives that greatly exceeds the total U.S. population.

• Claims processing and pharmacy network management. The figures for the largest companies include an unknown number of claims from smaller PBMs. That’s because many smaller PBMs outsource claims processing and fulfillment to one of the three largest PBMs. Smaller PBMs with internal capabilities are included in the “All Other PBMs” category.

• Discount cards and cash-pay prescriptions. Patient-paid prescriptions that use a discount card are not considered cash-pay, because the claims are adjudicated by a PBM. A growing (but undisclosed) share of discount card claims are included within the figures for each PBM.
  
  We reserve the term cash-pay prescription for claims that are not submitted and adjudicated, so a PBM or third-party payer has no record of drug utilization. Instead, the patient is the payer and there is no PBM involvement.