Pharmacy Benefit Managers love to talk about savings. They talk about discounts, rebates, guarantees, high performance networks, and aggressive formulary management. They showcase spreadsheets that appear airtight and confident. They promise the plan sponsor a clean and predictable story about how their pharmacy benefits will be managed and how much money the plan will save. And for years, most employers have taken those promises at face value because the numbers look impressive, the proposals look scientific, and the PBM industry has been allowed to define its own grading system.

The problem is that nearly every number a PBM provides is either incomplete, misaligned with reality, or structured in a way that leaves the employer believing they are getting one thing while actually paying for something very different. That gap between what is promised and what is truly paid is where PBM net performance becomes one of the most important concepts in pharmacy benefits today. Yet most plan sponsors never see it. They see chunks of it. They hear pieces of it. But they rarely see the full net picture.

Understanding PBM net performance is not about being suspicious. It is about being informed. It helps a plan sponsor understand what they actually paid on an all-in basis after every ingredient cost, every dispensing fee, every network adjustment, every rebate arrangement, every administrative carve out, every specialty markup, and every utilization steering tactic is finished. It is the only view that truly reveals what the employer got in exchange for the promises made at the proposal stage.

The industry makes this difficult on purpose. Every PBM has its own language, its own definitions, its own rebate categories, its own MAC lists, its own network tiers, and its own reporting templates. Most sponsors are handed reports that are tidy but not transparent. They are shown the pieces that make the PBM look strong and are shielded from the pieces that would raise real questions. Because of this, plan sponsors often assume their plan is performing well when in reality they are simply being shown the curated version rather than the complete story.

To understand how different the curated version can be from the truth, imagine an employer that compared two PBMs based on the usual proposal language. The first PBM offers aggressive discounts, impressive rebates, and zero administrative fees. Everything looks perfect. The second PBM offers lower discounts, lower rebates, and a per-member administrative fee. On paper, the first proposal wins by a mile. A CFO would naturally lean toward the bigger numbers and the smaller fees, and no one would blame them for it.

But when the plan year finishes, the employer who chose the first PBM discovers that the real net cost of their pharmacy benefit is far higher than expected. Ingredient costs were padded through benchmark choices that made discounts meaningless. Rebates were promised but partially withheld through definitions that allowed the PBM to reclassify drugs in ways the sponsor could not see. Specialty drugs, which represent most of the spend, were marked up heavily because they were exempt from the guarantee language. And the drug mix shifted in ways that benefited the PBM financially at the expense of the employer. When the employer looks at the actual data, the true all-in cost per prescription is significantly higher than what the proposal led them to believe.

Meanwhile, the employer who chose the second PBM with the less exciting proposal ends up paying dramatically less over the course of the year. That PBM used acquisition-based pricing, passed through real rebates without hidden categories, and did not pad ingredient cost. They managed utilization through clinical integrity rather than revenue motives. Their guarantees were tighter, cleaner, and backed by real performance. Because of that, their final net cost per prescription was far lower even though their proposal appeared weaker at first glance.

This is the core misunderstanding that exists in the market today. The PBM that looks strongest on paper is often the PBM with the most room to manipulate the underlying economics. The PBM that looks less exciting on paper is often the PBM that is avoiding the very games that inflate cost. Net performance is the only measure that cuts through that entire system of smoke and mirrors. It ignores the promises and focuses on the actual dollars. It reveals who delivered value and who simply delivered a polished proposal.

The challenge is that many employers do not know how or when they are allowed to see the PBM’s true net performance. Some only see quarterly reports that highlight savings categories without revealing the mechanics behind the numbers. Some are given annual reconciliation statements that appear official but are based entirely on the PBM’s definitions rather than objective financial reality. Others receive rebate checks without knowing what the total rebate pool actually was. A few receive ingredient cost summaries that mask the fact that ingredient cost is not the same as acquisition cost. And nearly all of them receive “savings” reports that compare the plan to the PBM’s own benchmark, which is like being graded by the company that sold you the test.

A plan sponsor sees the PBM’s true net cost only when they are given access to the complete data set without filters, disclaimers, missing fields, or proprietary exclusions. That data must include claim-level details, acquisition-aligned pricing, gross and net cost fields, full rebate categories, and a clear view into the specialty channel. When that data is analyzed comprehensively and consistently, the sponsor can see the true cost per script across all drugs, all channels, and all categories. That is net performance. It is the PBM’s report card, not the PBM’s marketing sheet.

When a plan sponsor sees true net cost for the first time, the reaction is almost always the same. They realize that they have been looking at the pharmacy benefit through a keyhole rather than a window. They realize how many loopholes exist in their guarantees. They realize how many dollars were quietly shifted from one category to another. They realize how much of their spend was influenced by incentives that did not align with their own. And they realize why pharmacy costs kept rising despite promises of aggressive savings.

This is also the moment many employers reach out to Acumen—because seeing the full net picture is powerful, but understanding how to correct course is where the real value lies. Acumen steps in when a sponsor wants not only visibility but guidance: someone who can interpret the data, expose the structural issues driving cost, and negotiate a benefit design that removes games instead of creating new ones. In short, Acumen helps at the exact point where information becomes action.

This is why net performance is becoming the future of PBM evaluation. Employers are tired of being given fragmented pieces of a puzzle that never fit together. They are tired of being told that their plan is performing well while their costs keep climbing. They are tired of the idea that transparency means simply receiving a report rather than receiving the truth.

The good news is that more employers are beginning to demand a full net cost analysis before they renew, before they switch, and before they agree to new guarantees. They want to see the real bottom line. They want to know what they actually paid. They want accountability instead of anecdotes. And when they ask for this level of clarity, PBMs respond very differently. The PBMs that rely on spread, inflated benchmarks, and rebate games become uncomfortable. The PBMs that operate cleanly and transparently welcome the analysis. That difference alone tells the employer everything they need to know.

If more sponsors evaluated PBMs through the lens of net performance rather than proposal theatrics, the industry would shift. The games would weaken. The pricing manipulation would shrink. The incentive structures that drive unnecessary costs would lose power. And employers would regain control of one of the most unpredictable components of their health plan.

PBM net performance is the great equalizer. It ignores the noise. It neutralizes the games. It reveals the truth. And most importantly, it empowers plan sponsors to make decisions based on accurate information rather than illusion.

The moment a plan sponsor sees their PBM’s true net cost is the moment they stop managing their pharmacy benefit in the dark. It is the moment they reclaim control. It is the moment they can finally hold their PBM accountable. And in an industry built on opacity, that moment is everything.