This paper evaluates the causal effects of changes in reference prices (RP) on prices, copayments, and overall expenditures for off-patent pharmaceuticals. With reference pricing, firms set prices freely and the health plan covers the expenses only up to a certain threshold. We use quarterly data of the German market for anti-epileptics at the package level and at the active substance level and exploit that the RP has been adjusted in some of the active substances but not in others in a difference-in-differences framework. At the product level, we find that a lower RP reduces prices for both brand-name drugs and generics, but leads to higher copayments, especially for brand-name drugs. At the aggregate level, we find that a lower RP leads to savings for the public health insurer since revenues decrease substantially for brand-name firms and, to a lesser extent, also for generic firms. Overall expenditures (payments by the health insurer and the patients) for brand-name drugs decrease in proportion to the decrease in the RP, while the adjustment does not significantly influence overall expenditures for generics
