廠商為了求取利潤，永續經營，必須規劃策略，發展自己的競爭優勢。藉由發送贈品的促銷，建立或找出讓目標消費群，產生購買自己商品或服務的意願，從而引發實際交易行為，便是常見的銷售策略。雖然時時可見到廠商贈品的促銷，但是相對於其他的銷售策略而言，例如廣告及折價券的研究，廠商發送贈品的行為，不論在實務面或理論面，皆缺乏系統化的整理，亦沒有嚴謹的經濟理論加以分析。 另一方面，參酌各國管制廠商競爭行為的反托拉斯法規，多已將廠商贈品促銷活動納入規範。進一步觀察，各國以法規面認為應該「適當」限制贈品，甚至是嚴格「禁止」贈品活動舉辦的理由，除缺乏系統化的經濟理論檢驗其是否正確外，對於應該如何來規範贈品的促銷，方可真正落實維護交易秩序與消費者利益，確保公平競爭以提高社會福利，目前亦無相關的探討。 綜上，本文關於「雙占廠商贈品之經濟分析」之研究目的，主要即欲探討贈品促銷對於社會福利的影響，以及規範贈品促銷能否提昇社會福利。為達成研究目的，本文藉由架構雙占廠商贈品促銷的簡單模型，援引「猜測變量」的分析方法，並在價格設定的模式下，探討雙占廠商「贈品的猜測變量」及其大小關係，對於廠商的各項均衡條件的影響。最後，本文將分析政府管制雙占廠商的贈品促銷能否提昇社會福利，進而討論政府管制贈品促銷的福利效果。

Giving a special gift with a purchase has become one of the favorite marketing tools used by enterprises. Besides, it is also one of the most familiar activities of consumers. The motivation provided by business gifts not only in regard ωin-house sales forces, but also other competitors' strategies, can have a significant impact on the achievement of sales goals. Past studies focused almost entirely on the issues of advertising or coupons, and therefore studies on gift promotion are relatively few. Since the value of business gifts offered by enterprises as marketing strategies is very important, a formal study on business gifts from the point of view of the economic welfare aspect is deemed necessary. By contrast, the basis for a business gift is not merely the prices or quality of the firm’s products, but is rather some other benefit to the consumer, including a specific reward. According to different fair trade laws (FTLs) around the world, it is provided that “no enterprise shall have any of the following acts which are likely to lessen competition or to impede fair competition.” Thus enterprises that conduct promotional campaigns such as gifts-with-purchase might be in violation of the FTL. To facilitate the effective handling of cases involving suspected unfair competition under the FTL, the competition authorities in countries such as Japan, Korea and Taiwan have formulated guidelines on the handling of business gifts. However, while guaranteeing government intervention in this promotional activity would be better for competition or for social welfare, more in-depth theoretical economic analysis has yet to be performed. The main purpose of this article is to provide an economic framework to discuss the regulatory effect of business gifts based on social welfare criteria. Although the gift actions of the individual firms in an industry are affected by the gift actions of the other firms under the duopolistic situation, based on the conjectural variation approach, whether or not the equi1ibrium condition and social welfare are affected by the market’s structure or competitors’ strategies is examined. Furthermore, some implications could be concluded for welfare measurement under government regulations regarding business gifts.