A pharmacy benefit manager, or PBM, is the company your health insurer or employer hires to run the prescription drug side of your coverage. It decides which medications your plan covers, which pharmacies you can use, and how much you pay at the counter. Three companies — CVS Caremark, Express Scripts, and OptumRx — dominate the industry, and together with three other large firms they handle roughly 95 percent of prescriptions filled in the United States.1Federal Trade Commission. FTC Releases Interim Staff Report on Prescription Drug Middlemen You probably never see the PBM. You just see the results at the pharmacy window.
What a PBM Does
A PBM performs four connected jobs. It builds the formulary, the list of drugs your plan covers. It contracts with pharmacies to form a network. It processes claims in real time when you fill a prescription. And it negotiates rebates from drug manufacturers in exchange for favorable placement of their drugs on the formulary.
When you hand your insurance card to the pharmacist, the pharmacy sends an electronic claim to the PBM within seconds. The PBM’s system checks whether you’re eligible, whether the drug is on the formulary, whether prior authorization or step therapy applies, and whether the dosage is within approved limits. It then calculates your copay or coinsurance and tells the pharmacy to dispense. All of that happens before you finish signing the screen. If the claim is denied, the PBM has to give a reason, and your doctor can submit documentation to appeal.2ACL (Administration for Community Living). An Advocate’s Guide to Appealing Prescription Drug Denials
The Big Three and Why Vertical Integration Matters
Each of the three largest PBMs is part of a bigger healthcare company that also owns an insurer and pharmacies. CVS Caremark sits alongside Aetna and CVS retail stores. Express Scripts is under Cigna’s Evernorth division with Accredo specialty pharmacy. OptumRx pairs with UnitedHealthcare and Optum’s pharmacy operations.
That structure creates a conflict the Federal Trade Commission has flagged: a PBM that also owns pharmacies has reason to steer prescriptions to its own locations and reimburse them more than competitors. The FTC’s second interim report found that the three largest PBMs marked up numerous specialty generic drugs dispensed at their affiliated pharmacies by hundreds or even thousands of percent, generating over $7.3 billion in revenue above estimated acquisition costs between 2017 and 2022.3Federal Trade Commission. FTC Releases Second Interim Staff Report on Prescription Drug Middlemen Cancer, HIV, and other specialty drugs were among the hardest hit.
How PBMs Make Money
Understanding how PBMs earn revenue is the fastest way to see why drug prices work the way they do. There are several channels, and they aren’t mutually exclusive.
Administrative fees are the simplest: a per-claim processing charge, usually a few dollars per prescription. Spread pricing is different. The PBM charges your insurer one price for a drug and reimburses the pharmacy a lower amount, keeping the difference. The FTC estimated that spread pricing on specialty generic drugs alone generated about $1.4 billion for the three largest PBMs over a five-year period.3Federal Trade Commission. FTC Releases Second Interim Staff Report on Prescription Drug Middlemen
A pass-through model does the opposite. The PBM bills the insurer exactly what it pays the pharmacy, plus a disclosed administrative fee. There’s no spread, though the disclosed fee may be higher. Finally, PBMs negotiate rebates from drug manufacturers and may keep a percentage rather than passing all of the rebate through to the plan. The contract between the PBM and your insurer determines which model applies and how much you actually see in savings.
How PBM Decisions Show Up in Your Prescription
The formulary is where most of the friction happens. If your drug isn’t on it, the pharmacy claim gets denied. If a cheaper alternative exists, the PBM may require you to try it first — step therapy — and document that it didn’t work before covering the more expensive option. Prior authorization is a separate hurdle: your doctor has to submit paperwork showing the drug is medically necessary before the PBM will approve it.
The logic is cost control. The consequence is delay, sometimes for medications your doctor already knows you need.
New 2026 Deadlines for Prior Authorization
Starting January 1, 2026, a CMS rule requires Medicare Advantage plans, Medicaid managed care plans, and CHIP programs to respond to prior authorization requests within 72 hours for urgent requests and seven calendar days for standard requests.4Centers for Medicare & Medicaid Services. CMS Interoperability and Prior Authorization Final Rule CMS-0057-F Denials must include a specific reason, which gives you something concrete to work with on appeal. Qualified health plans on the federal exchange were already operating under a 72-hour expedited and 15-day standard timeline, and that stays the same.
Pharmacy Networks and Where You Can Fill
PBMs build networks of pharmacies that agree to dispense at negotiated reimbursement rates. Some networks are broad. Others are narrow, and within them a “preferred” pharmacy usually means lower cost-sharing for you. Out-of-network pharmacies may cost more or not be covered at all.
Independent pharmacies have taken the hardest hit. They lack the bargaining power of chains and often receive lower reimbursement rates. The FTC found that PBM practices can squeeze independent pharmacies that Americans in rural communities depend on for essential care.1Federal Trade Commission. FTC Releases Interim Staff Report on Prescription Drug Middlemen When a PBM steers patients toward its own affiliated pharmacies while paying unaffiliated ones less, closures follow, especially in underserved areas.
One recent change helps pharmacies plan their finances. As of January 2024, CMS eliminated retroactive Direct and Indirect Remuneration (DIR) fees in Medicare Part D. PBMs used to claw back money from pharmacies months after a prescription was dispensed, based on performance metrics the pharmacy might not have known about. Now, all price concessions have to be reflected in the negotiated price at the point of sale. Performance-based fees are still allowed, but they must be applied upfront through bonus payments rather than retroactively.
Rebates and Why They Don’t Lower Your Copay
Rebates are the least transparent part of the PBM business. Drug manufacturers pay PBMs rebates in exchange for preferred formulary placement, essentially paying for access to the PBM’s covered patients. These payments apply mostly to brand-name drugs and can be a large share of the drug’s list price.
Here is what that means for you. Your copay or coinsurance is typically calculated on the drug’s list price, before any rebate is applied. So even when a PBM negotiates a large rebate, you may pay the same amount at the counter as if no rebate existed. The rebate flows back to the insurer or plan sponsor and may lower premiums broadly, but it doesn’t reduce what an individual patient pays for that specific prescription. Some contracts pass all rebates through to the plan. Others let the PBM keep a share.
There is a second consequence. Because rebates favor higher-priced brand-name drugs, a PBM may prefer a brand with a large rebate over a cheaper generic with none. The FTC found that rebate agreements between PBMs and brand manufacturers are sometimes explicitly conditioned on limiting access to lower-cost generic and biosimilar competitors.1Federal Trade Commission. FTC Releases Interim Staff Report on Prescription Drug Middlemen
Medicare Part D Changes in 2026
Two changes under the Inflation Reduction Act are reshaping what PBMs can do inside Medicare Part D.
First, Medicare Part D now has an annual out-of-pocket spending cap of $2,100 in 2026. Once you hit that ceiling, you pay nothing for covered Part D drugs for the rest of the calendar year.5Medicare.gov. Medicare and You Handbook 2026 Before this change, there was no hard cap, and beneficiaries with expensive prescriptions faced thousands in annual spending.
Second, for the first time Medicare can directly negotiate prices on certain high-cost drugs. The negotiated prices, called Maximum Fair Prices, took effect January 1, 2026 for an initial group of ten drugs, including Eliquis, Jardiance, Xarelto, Januvia, and Entresto.6Centers for Medicare & Medicaid Services. Selected Drugs and Negotiated Prices Part D plans must cover these drugs at the negotiated prices.7Centers for Medicare & Medicaid Services. Medicare Drug Price Negotiation Program: Negotiated Prices for Initial Price Applicability Year 2026 That takes the traditional PBM leverage of rebate-driven pricing off the table for those specific drugs, because the federal government sets the price.
Your Rights and What You Can Do
A few consumer protections are worth knowing about, and a few habits can save you real money.
Pharmacists used to be barred by “gag clauses” from telling you when paying cash for a prescription would be cheaper than using your insurance. The Patient Right to Know Drug Prices Act ended that practice for all health plans.8GovInfo. Patient Right to Know Drug Prices Act So ask. On inexpensive generics, the cash price is often lower than the insurance copay.
If your PBM denies coverage, you have the right to appeal. The process usually starts with an internal appeal, where your doctor submits documentation of medical necessity. If that’s denied, you can request an independent external review. Medicare Part D has multiple appeal levels: redetermination by the plan, review by an Independent Review Entity, then administrative judges, and potentially federal court.2ACL (Administration for Community Living). An Advocate’s Guide to Appealing Prescription Drug Denials Many states also require PBMs to maintain an exceptions process for medically necessary drugs that aren’t on the standard formulary.
A few practical things to try:
- Ask your pharmacist to compare your copay against the cash price before you fill a prescription.
- Check whether your plan lists preferred pharmacies with lower cost-sharing.
- If your doctor prescribes a brand-name drug, ask whether a generic would work. Rebate incentives sometimes push plans toward the pricier option.
- Appeal any denial. The first decision is automated, and clinical documentation from your doctor often flips it.