Parallel trade, price discrimination, investment and price caps
研究平行贸易（未经制造商许可的跨市场转售）对制造商投资质量、开发不同质量版本产品的影响，并考虑价格上限和强制许可的作用。发现考虑投资激励后，平行贸易更可能降低整体福利，尤其在研发密集型产品（如药品）中；但价格上限下平行贸易的危害较小。
type="main" xml:lang="en"> Parallel trade is the resale of a product by a wholesaler in a market other than that intended by the manufacturer. One of its consequences is that manufacturers may be prevented from price discriminating between markets that have different willingness to pay for the product in question. Some legal regimes give the manufacturer the right to prohibit parallel trade, but others do not. We examine the policy implications of parallel trade in a world in which manufacturers invest in product quality, and have the possibility to develop different quality variants of their goods. We also consider the possibility that the authorities may impose price caps and compulsory licensing (as commonly occurs for some pharmaceutical products). We find that taking investment incentives into account makes parallel trade much less likely to enhance overall welfare, which implies that parallel trade in products intensive in R&D, such as pharmaceuticals, is less desirable than in fields such as branded consumer products. We also find that, somewhat surprisingly, the threat of parallel trade does not induce firms to market inferior versions of their products in poor countries. However, parallel trade is less likely to be detrimental to welfare when there are price caps, since compulsory licensing can mitigate the major cost of parallel trade (namely a refusal to supply a poor country market). — Stefan Szymanski and Tommaso Valletti