Inside the Plan: Employer-Funded PBMs Compared, 19 Side by Side
A pharmacy benefit manager runs the drug benefit inside your health plan, so its spend counts toward the deductible and shows in claims data. This page compares every PBM we cover, from the three largest to the transparent and direct-source alternatives. Looking for discount cards, cash-price pharmacies or manufacturer programs? Those sit outside the plan: see the outside-the-plan comparison. Back to the main guide.
All 19 PBMs, One Table.
Type, who pays, how each PBM relates to the plan, and whether spend counts toward the deductible. Click any PBM for its page.
| Option | Type | Who Pays | Plan Relationship | Counts Toward Deductible |
|---|---|---|---|---|
| SmithRx | PBM | Plan | Inside the plan | Yes |
| Capital Rx | PBM | Plan | Inside the plan | Yes |
| ScriptGuideRX | PBM | Plan | Inside the plan | Yes |
| Navitus | PBM | Employer plan | Inside the plan | Yes, through the plan |
| AffirmedRx | PBM | Employer plan | Inside the plan | Yes, through the plan |
| Rightway | PBM | Employer plan | Inside the plan | Yes, through the plan |
| ProCare Rx | PBM | Employer plan | Inside the plan | Yes, through the plan |
| MC-Rx | PBM | Employer plan | Inside the plan | Yes, through the plan |
| CVS Caremark | PBM | Employer plan | Inside the plan | Yes, through the plan |
| Express Scripts (Evernorth) | PBM | Employer plan | Inside the plan | Yes, through the plan |
| Optum Rx | PBM | Employer plan | Inside the plan | Yes, through the plan |
| Prime Therapeutics | PBM | Employer plan | Inside the plan | Yes, through the plan |
| CarelonRx | PBM | Employer plan | Inside the plan | Yes, through the plan |
| CenterWell Pharmacy (Humana) | PBM | Employer plan | Inside the plan | Yes, through the plan |
| MedImpact | PBM | Employer plan | Inside the plan | Yes, through the plan |
| Kaiser Pharmacy | PBM | Employer plan | Inside the plan | Yes, through the plan |
| Scripius (Intermountain) | PBM | Employer plan | Inside the plan | Yes, through the plan |
| HealthPartners | PBM | Employer plan | Inside the plan | Yes, through the plan |
| SS and C Health | PBM | Employer plan | Inside the plan | Yes, through the plan |
What Each PBM Is, and What to Watch For.
Every pharmacy benefit manager we cover, from the three largest to the transparent and direct-source alternatives. Descriptions come from each PBM’s own published materials and press coverage, and are not recommendations. See the full employer-funded PBM guide for market-share data.
| PBM | What It Is | Watch For |
|---|---|---|
| ScriptGuideRX (SGRx Health) | Describes cost-effective prescription benefit management without compromising quality or service. Its site also lists SGRXSaves savings, 340B administration, a TPA service, non-opioid support and a HealthChoice of Michigan program. | Ask which of those services you would actually use, and which are priced separately. |
| Navitus | Owned by SSM Health and Costco, per Healthcare Brew. It charges an administrative fee per member per month, says it takes no spread and says it passes on 100% of savings. | It is vertically integrated with its specialty pharmacy, Lumicera. Ask how that pharmacy is used and how it is paid. |
| AffirmedRx | Started in 2021 and named by Healthcare Brew among the transparent alternatives gaining traction. 7-Eleven and Purdue University were reported as clients. | A newer vendor means a shorter track record. Ask for references with a similar plan size. |
| Rightway | Founded in 2017 and reported to have moved Tyson Foods away from Caremark in early 2024. It markets transparent fee models. | Large-employer references may not match your plan size. Ask for peers. |
| ProCare Rx | The PBM behind MC-Rx, which describes itself as powered by ProCare Rx. MC-Rx reported in December 2024 that ProCare Rx earned full URAC reaccreditation in pharmacy benefit management. | MC-Rx and ProCare Rx are separate brands on one platform. Ask which entity signs your contract and who answers your claims questions. |
| MC-Rx | A direct-source PBM, powered by ProCare Rx, with offices in Gainesville, Georgia and Caguas, Puerto Rico. It says it controls its own systems, pharmacy contracts and claims processing, and passes rebates through. | Its figure that over 90% of PBMs lack their own pharmacy networks and claims platforms is its own 2023 claim. Ask for evidence and for current client references. |
| CVS Caremark | One of the Big 3, owned by CVS Health, with 18% of rebate negotiation in 2024 per the AMA’s 2026 update. In August 2026 the FTC announced a proposed settlement with Caremark that would require a standard offering passing rebates through at the point of sale and letting plan sponsors move off rebate guarantees and spread pricing, per Lockton. | The order is proposed, and the terms apply to a standard offering. Ask what Caremark is actually offering you and how it changes the timing of rebate dollars in your budget. |
| Express Scripts (Evernorth) | One of the Big 3, part of Cigna’s Evernorth, with 23% of rebate negotiation in 2024 per the AMA’s 2026 update, up from 17% in 2022. It introduced a fee-based, rebate-free model in October 2025, now called Signature Pharmacy Benefit Services. Cigna Healthcare fully insured clients start in 2027, and it becomes the standard for all Evernorth pharmacy benefit clients in 2028, per Darwin Research Group. | Evernorth owns the PBM and affiliated pharmacies. Ask how affiliated pharmacies are paid and what happens to your guarantees. |
| Optum Rx | One of the Big 3, part of UnitedHealth Group, with 23% of rebate negotiation in 2024 per the AMA’s 2026 update. In May 2026 it announced a fee-based model with a monthly fee per member, meant to eliminate spread pricing, to be offered to all clients by the end of 2027. Clients are not required to move right away, and its fees, including those tied to its group purchasing organization Emisar, are to be disclosed. | A fee-based model changes how the PBM earns money. Ask for the full fee schedule and for payments from manufacturers in writing. |
| Prime Therapeutics | The fourth-largest PBM in the AMA’s 2026 update, with 11% of rebate negotiation in 2024. Several Blue Cross Blue Shield insurers jointly own it, and it is almost exclusively used by BCBS insurers, including some that do not own it. | Ask which BCBS plan relationships bring you to Prime, and what you can negotiate separately. |
| CarelonRx | Elevance Health’s PBM, with 8% of rebate negotiation in 2024 per the AMA. It was initially used only by its owner and is still largely used by it, and it is now also used by another BCBS insurer. | If your carrier is an Elevance plan, ask whether the PBM is bundled and whether you can carve it out. |
| CenterWell Pharmacy (Humana) | Humana’s PBM, with 5% of rebate negotiation in 2024 per the AMA, down from 7% in 2022. It is used exclusively by its owner. Drug Channels put Humana Pharmacy Solutions at 7% of 2025 prescription claims. | The AMA says it serves Humana only, so it is not an option for most employers outside a Humana plan. |
| MedImpact | An independent PBM. The AMA lists MedImpact and SS and C Health as the only PBMs in its top 10 for retail network management and claims adjudication that are not affiliated with a health insurer. Drug Channels put MedImpact at 5% of 2025 prescription claims. | Ask for the contract terms and client references like any other PBM. Independence does not by itself mean lower net cost. |
| Kaiser Pharmacy | Kaiser’s own PBM, with 8% of rebate negotiation in 2024 per the AMA, down from 9% in 2022. The AMA says it is used exclusively by Kaiser. | It is not available to employers outside a Kaiser plan. It matters mainly as a sign of how much of the market sits inside insurers. |
| Scripius (Intermountain) | The PBM of Intermountain, with 1% of rebate negotiation in both 2022 and 2024 per the AMA. The AMA lists it as the ninth-largest PBM. | It is a health-system and insurer-owned PBM. Ask whether it serves employers outside that system before you consider it. |
| HealthPartners | The AMA calls the tenth-largest “PBM” an integrated insurer and health system that negotiates rebates in house, with a share under 1% in 2022 and 2024. | It is in the data as an insurer doing the work itself, not as a PBM you would hire. |
| SS and C Health | Named by the AMA, along with MedImpact, as one of the only two PBMs in its top 10 for retail network management and claims adjudication that are not affiliated with a health insurer. Its claims adjudication share was 1% in 2024, down from 2% in 2022. | It is a small, independent name. Ask for the same pricing, audit and reference terms you would ask of any PBM. |
| SmithRx | A transparent PBM that claims savings of 20% or more. See its page for the details. | Read the SmithRx page |
| Capital Rx | A PBM founded in 2017 and now part of Judi Health. See its page for the details. | Read the Capital Rx page |
The 10 Largest PBMs in the U.S.
Rebate-negotiation market share across commercial and Medicare Part D, from the AMA’s 2026 update using 2022 and 2024 data. Shares are rounded, so they do not sum exactly.
| Rank | PBM | Co-Owned Insurer | 2024 Share | 2022 Share |
|---|---|---|---|---|
| 1 | OptumRx | UnitedHealth | 23% | 21% |
| 2 | Express Scripts | Cigna | 23% | 17% |
| 3 | CVS Caremark | Aetna (CVS Health) | 18% | 21% |
| 4 | Prime Therapeutics | Blue Cross Blue Shield plans | 11% | 10% |
| 5 | Kaiser Pharmacy | Kaiser | 8% | 9% |
| 6 | CarelonRx | Elevance Health | 8% | 8% |
| 7 | CenterWell Pharmacy | Humana | 5% | 7% |
| 8 | Navitus | SSM Health and Dean | 1% | 1% |
| 9 | Scripius | Intermountain | 1% | 1% |
| 10 | HealthPartners | Self (in-house) | Under 1% | Under 1% |
A different measure, prescription claims processed in 2025 per Drug Channels Institute, ranks Express Scripts at 31%, CVS Caremark at 26%, Optum Rx at 23%, Humana Pharmacy Solutions at 7%, MedImpact at 5% and Prime Therapeutics at 3%. The three largest control about 80%. Source: AMA Policy Research Perspectives, September 2026; Drug Channels Institute via Becker’s.
Comparison Questions.
Quick answers before you read the individual PBM pages.
How is a PBM different from a discount card?
A discount card is something an employee uses outside the plan. A PBM is the vendor an employer or plan sponsor buys to run the pharmacy benefit, so its spend sits inside the plan and counts toward the deductible. See the outside-the-plan comparison for the employee-side options.
Which PBMs are the largest?
Express Scripts, CVS Caremark and Optum Rx are the three largest by market share. The market share table on this page shows the latest figures we sourced. Try our free pharmacy rebate value calculator to run the numbers for your own group.
Can a fully insured employer choose a PBM?
Usually not. In a fully insured plan the carrier controls the PBM, so a PBM bid generally applies to self-funded plans. Confirm how your own plan is funded first.
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