本文以探討『買貴退差價』與默契性聯合行為間之關係為主題，假設市場上只有兩家廠商，分別以同質商品與異質商品研究『買貴退差價』對默契性聯合行為難易度之影響，本文與大多數文獻一樣，使用折現值的大小代表維持聯合行為之難易度，本文假設市場一開始即處於廠商間已經有默契性聯合行為之狀態，之後再加入『買貴退差價』探討對於默契性聯合行為之影響，而本文發現，當加入買貴退差價時，與在沒有買貴退差價時更容易有默契性聯合行為發生，且在同質商品時當越多消費者選擇退費則越容易促進聯合行為，在異質商品時，除了與同質商品結論相同，也發現當兩家廠商商品替代性越大時，默契性聯合行為困難維持，而本文皆假設廠商間為Cournot競爭。

The purpose of this paper is discussing the relation between tacit collusion and price matching policy. There are two firms in the market, and we study the effects of price matching policy on collusion. Following the literature we use discount factors to measure difficulties while maintaining collusion. In conclusion, tacit collusion appears more often after employing price matching policy, and we also find that tacit collusion is easier to facilitate when more consumers request refund on both homogeneous and heterogeneous products. We also find that, with heterogeneous goods, it can be difficult to maintain collusion by firms when product are more substituted. Besides, we assume firms are employing Cournot competition in this paper.

審定書.......................................................................................................i
授權書......................................................................................................ii
誌謝.........................................................................................................iii
摘要.........................................................................................................iv
Abstract...................................................................................................v
第一章 緒論..............................................................................................1
第一節 研究背景與研究動機.......................................................................1
第二節 文獻回顧與研究方法........................................................................3
第二章 模型設定與求解-在同質產品假設下...................................................9
第一節 廠商間合作均衡折現值之推導..........................................................9
第二節 無『買貴退差價』時折現值之推導...................................................11
第三節 有『買貴退差價』時折現值之推導...................................................14
第四節 有『買貴退差價』且加入對手廠商之也可採取相同策略......................16
第三章 異質產品與同質產品之比較.............................................................19
第一節 異質產品在無『買貴退差價』時折現值推導......................................19
第二節 異質產品有『買貴退差價』時折現值推導.........................................21
第三節 同質產品與異質產品維持聯合行為所需之最小折現值之比較...............22
第四章 結論.............................................................................................27
參考文獻.................................................................................................28

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