The amount of rebate paid by pharmaceutical manufacturers to PBMs is dependent on which of the following conditions?

The amount of rebate paid by pharmaceutical manufacturers to Pharmacy Benefit Managers (PBMs) is closely linked to the market share of dispensed prescriptions. Rebates are strategically designed to incentivize PBMs to favor certain medications over others, as a higher market share typically means that a drug is being prescribed and dispensed more frequently within a given therapeutic class.

Pharmaceutical manufacturers may offer larger rebates for products with lower market share to encourage PBMs to promote their drugs more heavily, creating a competitive advantage in formulary placements. As a drug gains market share, its necessity to offer substantial rebates decreases, as it has already established a foothold among prescribers and patients.

The other conditions mentioned can play a role in the dynamics between manufacturers and PBMs, but they do not directly correlate as strongly with the rebate amounts as market share does. A preferred status on a PBM's list may enhance the likelihood of a product being used but might not affect actual rebate amounts as much as the market share does. Similarly, being included in the formulary or comparisons to other products may influence a manufacturer's rebate strategy, but these are often secondary factors relative to the direct market dynamics.