訊息分享的議題一直是各國反托拉斯當局關心的重點之一，廠商彼此之間過度的訊息交換容易導致競爭對手間的價格或數量勾結，因而抵觸反托拉斯法規。本篇論文運用創新的替代函數分析
法(Replacement Function Approach)探討寡占廠商間的訊息分享問題，假設廠商對其競爭對手之成本具備不完全訊息，比較分享與不分享訊息下之預期均衡利潤，結果發現廠商具有分享訊息的誘因。本文提供了一個比傳統文獻習慣採用之最適函數分析法(Best Response Function Approach)更有力的分析工具，並延伸其範圍至部分廠商選擇不生產的均衡結果，結果顯示當所有廠商都為正產出時，成本差異性程度大小會影響廠商交換成本訊息的誘因，這樣的討論未曾有文獻觸及。

The issue of information sharing has always been important for the
perspective of antitrust authorities. Excessive sharing of previously unavailable information can lead to price or output collusion among competitors. This paper employs innovative replacement function approach to explore problems of information sharing among firms. In particular, it assumes that each firm has incomplete information about costs of its rivals, and proves that firms have incentive to share their cost information, based on the comparison of expected equilibrium profits of share and non-share situations. This paper provides a more powerful analysis tool than traditional best response function approach, and extends the concept to equilibrium results in which some firms may choose not to produce. It shows that the diversity of costs would influence firms’ incentive to exchange their cost information if all firms are active, which has never been discovered in the literature.