Four Companies Run Your Pharmacy Counter. Who Runs Them?

Four companies now control 75 percent of the national pharmacy benefit market. Two years ago they held 70 percent. Every patient who opened a surprise formulary letter this year dealt with one of those four, whatever the letterhead said. The plan that sets her premium, the company that writes her drug list, and the business that picks her pharmacy often answer to the same parent. So when her copay jumps in June, she calls the plan. The plan points at the PBM. The PBM points at the plan. Who in that loop negotiates for her?

The American Medical Association built its latest annual PBM analysis on prescription drug plan enrollment from 2022 and 2024. In 2024, OptumRx and Express Scripts each held 23 percent of the national market. CVS Caremark held 18 percent. Prime Therapeutics held 11 percent. The order shuffled. Express Scripts climbed from 17 percent to 23, and Caremark slid from 21 to 18. The total only grew.

The local picture runs harder. By the thresholds in federal antitrust guidelines, 32 local PBM markets rated highly concentrated in 2024. That equals 94 percent of the markets the AMA measured, up from 28 markets, or 82 percent, in 2022. A patient in one of those markets has no realistic second option. Her employer or her Part D plan picked the PBM, and the PBM picked everything after that.

Now the ownership. Each of the ten largest PBMs shares an owner with a health insurer. In 2024, 69 percent of people with commercial or Medicare Part D drug coverage sat with an insurer that owns or shares ownership with its PBM. In Part D the figure hits 73 percent. In commercial coverage it reaches 67. The AMA also points to research published by the American Economic Association. That study found insurer purchases of PBMs went with higher premiums for competing plans, and it found no evidence the parent passed any savings to its own enrollees as lower premiums. Consolidation promised efficiency. The receipts show a bigger parent.

Name the families, because the record already does. UnitedHealth Group owns UnitedHealthcare and OptumRx. The Cigna Group owns Express Scripts. CVS Health owns Aetna and Caremark. Prime Therapeutics answers to a group of Blue Cross and Blue Shield plans. Each family sets premiums, designs formularies, and runs pharmacy networks inside one set of books. Every patient-facing failure advocates log, the formulary swap nobody explained, the specialty pharmacy mandate that adds days to a fill, the copay that moves mid-year, comes out of that structure. Patients file each one under bad luck. The ownership chart files them under business model. AMA President Willie Underwood III put it plainly: these markets should "serve patients rather than reinforce the market power of large healthcare companies."

Manufacturers carry their own share. Pharma trades rebates for formulary position, and access teams celebrate the preferred tier. A preferred tier means little to a patient whose coinsurance still tracks the list price, because the rebate stops at the PBM and never reaches her. I have spent years measuring the distance between how companies grade their access work and how the advocates standing beside those patients grade it. The distance holds. ELAVAY, Archo's syndicated study, has asked patient advocacy organizations, professional societies, and community groups across more than 20 disease states every year since 2015 how biopharmaceutical companies behave as partners. Companies grade their own patient assistance well. The organizations they name as partners describe something different.

My own side does not escape this. Advocacy organizations sign the PBM reform letters and testify about access in general terms. Then ask how many member receipts the organization holds, sorted by plan and by PBM. For most, the honest count sits near zero. A reform fight built on anecdotes loses to four companies built on claims data.

The companies advocates trust measure the patient's out-of-pocket cost on every contract. They treat a won tier and a captured rebate as inputs, and they report what a patient on that tier actually paid at the counter. The median company reports the tier and stops. One of those numbers reaches a patient. The other reaches a slide.

They also bring advocacy organizations into formulary and access planning before contracting season, while that input can still change a term. And they build patient assistance that survives a formulary change, so a PBM decision in January cannot strand a patient halfway through therapy. Their ELAVAY scores show it.

Advocacy leaders, ask your plan and PBM partners in writing for patient out-of-pocket data by plan, and set December 31 as the deadline. Start collecting member receipts sorted by plan and PBM this quarter, and hand them to the AMA's TruthinRx campaign along with your community's stories. Pharma access and commercial leaders, pick one product this quarter and audit what a patient on the preferred tier actually paid, then put that number next to the rebate in your next business review.

If you want to see how advocates rate your patient assistance and partnership work against your peers, the 2025/2026 ELAVAY Report is available now, and fielding for 2026/2027 opens in October. If you want to know whether patient voice reaches your access decisions at all, take the Advocacy Influence Diagnostic at https://aid.elavay.com/survey. It is free, anonymous, and takes only five minutes. It returns an Advocacy Visibility Index and a Strategic Risk Score. Or write to me at [email protected].

American Medical Association, "AMA analysis: PBM market concentration continues to rise," press release, https://www.ama-assn.org/press-center/ama-press-releases/ama-analysis-pbm-market-concentration-continues-rise

AMA, Competition in PBM and prescription drug plan markets, 2026 (PDF), https://www.ama-assn.org/system/files/prp-pbm-shares-hhi-2026.pdf

American Economic Association study cited by the AMA, https://www.aeaweb.org/articles?id=10.1257/app.20240011

AMA TruthinRx campaign, https://truthinrx.org/