How PBM's and Government bargain

When the US government buys drugs, they penalize drug companies with huge taxes if they don't reach agreement.  From Marginal Revolution:  

The “negotiation,” if you want to call it that, is “your money or your life” and fairness has little to do with it. The IRA also requires very costly inflation rebates, i.e. a price control/tax.

This reduces the gains to innovation, equivalent to weakening patent protections at a time when the gains to innovation in pharma are big.

In contrast, the private sector uses PBM's to create bargaining competition to reduce drug prices (Froeb and Shor, 2023) 

For 181 million Americans not on Medicare or Medicaid but insured through their employer, labor union, or private insurance health plan, the primary restraints on pharmaceutical prices are pharmaceutical benefit managers (PBMs) who administer health plan drug benefits. PBMs use the aggregate demand of their constituent plan sponsor clients — employers, unions, government agencies, health insurers, and others — to negotiate lower prices

These PBM's create competition between drugs within a therapeutic class by setting up formularies (lists of covered drugs) for Health Plans. Drug manufacturers compete by offering lower prices to get onto the preferred tiers of formulary, those with lower co-pays.

... Consider Lipitor and Crestor, two leading statins, or lipid-lowering cholesterol medications. The placement of one drug on a more favorable tier than the other can considerably shift sales volume in favor of the preferred drug. Economists at MIT and Wharton estimate that the statin manufacturers are willing to offer rebates of up to 54% in return for favorable placement.