| Abstract: | 解決cartel 問題面臨最大的挑戰在於，一般的cartel 皆為廠商間非法運作之秘密協定。就競爭政策的角度而言，一價格操控理論 (a theory of price fixing) 所能帶來最之貢獻在於對促使勾結產生條件的鑑別，了解勾結下的價格特性，以及察覺是否有cartel 在市場中運作。雖然現有文獻已經就此些問題有相當多的討論，但目前研究皆忽略了一個相當重要的面向—由於勾結行為的非法性，cartel 成員不僅要制定內部穩定 (internally stable) 的價格來提升利潤，更要避免使人產生價格操控的懷疑。換言之，cartel 成員避免價格操控的懷疑以迴避偵查與cartel 內部的穩定性，實為同等重要的課題。本研究計畫之設計在於當cartel 選擇價格以迴避偵查的情況下，增進對cartel 價格動態知的認識。為達此一目的，本人提出兩個研究方向、為期兩年期之研究計畫。首先第一年之計畫「內生查獲機率下之cartel 價格動態」，目的在於了解在成本變動及買方可能懷疑有價格操控的情況下，cartel 之價格模式。實際而言，主管競爭政策之政府單位在有限資源的限制下，並不能主動的站在查稽cartel 的第一線，在許多cartel 的例子中通常是買方，尤其是當買方本身也是企業時，首先發現價格的異常。在此本人架構一個動態模型來說明買方如何在價格異常的情況下產生cartel 在進行價格操弄的懷疑，以及cartel 的決策模式。其中關鍵在於如何設定買方對價格變動之belief structure。本人建議將買方對價格變動的beliefs 決定於前期價格變動的beliefs、本期價格之變動、以及一個noisy cost signal。一旦設定買方預期誤差之分配情形後，就可以定義價格變動之相對可能性，以進一步討論異常之價格變動及cartel 之決策。第二年之計畫「內生cartel 形成下之cartel 價格動態」，目的在於提出內生cartel 形成之模型，以及在cartel 形成後，在成本變動及內生查獲機率下cartel 之價格模式。為使模型能成功的內生形成cartel，本人建議將非勾結解設為隨機。此一做法的用意在於，當非勾結情況下之報酬低於一定水準時，廠商會選擇成立cartel。畢竟就競爭政策的角度而言，一個成功的模型不僅僅在於cartel 的內生形成，更重要的是比較cartel 的價格模式與cartel 形成前，非勾結情況下的價格模式。最後，本研究計畫之成果不僅補足現有產業組織文獻在勾結價格研究上忽略了 cartel 成員積極迴避偵查誘因的漏洞，也為本人未來之待研究項目，例如了解競爭政策之有效性以及建立cartel 偵測機制等課題，奠定重要的基礎。
The major challenge to stopping cartels is that they are shrouded in secrecy. From an antitrust perspective, the essential tasks for a theory of price-fixing are identifying conditions that facilitate collusion, characterizing the properties of collusive pricing, and towards discerning the presence of a cartel. Although there is a large theoretical literature addressing these issues, work has generally failed to take account of an important dimension to this problem. Due to the illegality of collusion, firms not only want to achieve internally stable prices to raise profit but also want to avoid creating suspicions that a cartel is in action. In other words, avoiding detection is as crucial as deterring deviations by cartel members. This research project is designed to increase the body of knowledge of the dynamics of cartel pricing when cartels choose prices to actively avoid detection by the antitrust authorities. For this purpose, two lines of work are proposed as a two-year project. In the first year, the title “Cartel Pricing Dynamics with Endogenous Probability of Detection” (Part A) intends to characterize collusive pricing patterns in an environment with cost variability and when buyers may detect the presence of a cartel. As a matter of practice, the antitrust authorities, given the constraint in resources, do not actively engage in detection. But instead, it is often the buyers—industrial buyers in particular—who are on the first line of detection in many cartel cases. I build a model where buyers become suspicious when the 表 C011 共 4 頁 第 4 頁 observed prices are anomalous, and these suspicions may eventually lead to detection. The key is on the structure of buyer’s beliefs over price changes. I propose to allow buyers` beliefs over price changes to depend on the previous period`s beliefs of price changes, current period`s price change, and some noisy cost signal. Once specifying a distribution on those prediction errors, I can then define the relative likelihood of a series of prediction errors to characterize anomalous price changes and a cartel’s decision-making. In the second year, the title “Cartel Pricing Dynamics with Endogenous Cartel Formation” (Part B) intends to develop a satisfactory model of endogenous cartel formation where a cartel, once a coalition is formed, prices to avoid detection in an environment with cost variability and endogenous buyer belief formation. In order to generate cartel formation, I propose to make the non-collusive solution stochastic. The idea is that cartel formation would occur when the non-collusive solution is sufficiently competitive. After all, from an antitrust perspective, the task does not simply end at coming up with a model that successfully endogenizes cartel formation, but rather at using the model to simulate price paths that describe properties of the cartel price path and properties of the non-collusive price path preceding cartel formation. Finally, the successfulness of this research project not only fill in the hole in the current literature of collusive pricing which ignores the important incentive of cartel members price to avoid detection, it also lays out the foundation to future projects on my research agenda, such as accessing the effectiveness of antitrust practices and developing screening mechanism for the existence of a cartel |
