1998年7月17日歐洲最高法庭作成限制真品平行輸入EU之決議，這項判決主要源自於部分製造商的壓力。製造商認為灰市商人以搭便車（free-riding）的方式享受了品牌的聲譽以及廣告效果，確可能因為不當的販售行為而破壞品牌的價值與聲譽。一般而言，水貨對授權代理商的確會造成某種程度的傷害，然而對製造商的影響則較不明確。為探討這些製造商反對真品平行輸入EU的可能原因，本研究建立一個二階段子賽局模型，求解代理商與製造商之均衡。本研究結果發現，如果水貨對授權商品所產生的替代效果與低價效果越強，或授權商品之市場需求曲線越凸向原點，則水貨的增加將使製造商的利潤越低。因而過去文獻認為多重通路必能增加製造商利潤的結論，在水貨市場不一定成立。此外我們更進一步得到，當服務水準內生時，水貨數量的增加會造成製造商的批發價格與利潤下降的幅度進一步擴大。而反對真品平行輸入EU的製造商應屬於其產品之市場市場需求曲線較凸以及價格敏感度較高之廠商。

With the support of the European Commission and many EU governments, the European Court of Justice (ECJ) has effectively limited ‘gray’ goods imports into the EU market in July 1998. The manufacturers has strongly objected to such judgment, stating that gray marketers often maintain significantly higher gross profit margins simply because they not only take away market share but also free-ride on the promotional activities performed and customer services provided, by their authorized counterparts. It is generally believed that the existence of gray channels hurts authorized agents; however, its effects on manufactures are less clear. This paper sets up a two-stage sub-game perfect equilibrium model to examine the effects of gray products on authorized agents as well as manufacturers. It is found that as gray goods become sufficiently sensitive to the price of the authorized product, an increase in gray goods would induce consumers to substitute such goods for authorized product, an increase in gray goods would induce consumers to substitute such goods for authorized products, lowering the sales of the authorized channel and reducing the authorized agent's incentive to provide the service. As a result, as sales of the gray goods rise, the manufacturer's profits decline, with the decline intensifying as the gray goods become more price-sensitive. We can therefore conclude that those manufactures who are against parallel importation are those whose products are highly price-sensitive.