The Unexpected Consequences of Asymmetric Competition. An Application to Big Pharma

This paper shows that a pro-competitive shock leading to a steep price drop in one market segment may benefi t substitute products. Consumers move away from the cheaper product and demand for the substitutes increases, possibly leading to a drop in consumer surplus. The channel leading to this outcome is non-price competition: the competitive shock on the fi rst set of products decreases the firms' ability to invest in promotion, which cripples their ability to lure consumers. To assess the empirical relevance of these findings, we study the e ffects of generic entry into the pharmaceutical industry by exploiting a large product-level dataset for the US covering the period 1994Q1 to 2003Q4. We find strong empirical support for the model's theoretical predictions. Our estimates rationalize a surprising fin nding, namely that a molecule that loses patent protection (the originator drug plus its generic competitors) typically experiences a drop in the quantity market share-despite being sold at a fraction of the original price.