美國產物保險公司組織結構實證分析

Abstract

美國產物保險公司的組織結構一般可分為四大類：股份有限公司型態 (Stock)，相互公司型態 (Mutual)，相互保險社 (Reciprocal)及勞依茲 (Lloyds)。不同的組織型態之間各有其相對的優勢，因而在不同的條件下，保險公司會選擇對其最有利的型態來經營。本篇論文主要針對兩個議題來討論：(1)討論保險公司的組織結構由相互公司結構轉變成為股份有限公司結構(Demutualization;去相互化)，其再保險需求的變化為何。(2)討論保險公司的組織結構與保險通路之間的關聯性為何。 在議題(1)的研究中我們發現去相互化的保險公司明顯降低對非關係的再保險人(non-affiliated reinsurers)的再保險需求，但對其有關係的再保險人的再保險需求相對是增加的。此現象一個可能的解釋為去相互化的保險公司對再保險的使用為一種風險自留的態度，而並非風險移轉的做法。而如此做可以降低保險公司的再保險成本。本研究的結果亦顯示去相互化的保險公司在轉換後其整體的再保險需求（非關係的再保險人的再保險需求＋關係的再保險人的再保險需求）並沒有明顯的改變。另外一個有趣的發現為去相互化的公司在轉換之前對非關係的再保險人的再保險需求是增加的。 在議題(2)的研究中我討論美國產物保險公司如何選擇其組織結構型態及保險通路。由於以往的研究結果並未發現一致的結論，所以本研究使用美國產物保險公司2004年的資料及採用遞減式的方法(reduced form approach)來重新檢驗組織結構型態及保險通路之間的關聯性為何。我們透過遞減式的方法(reduced form approach)來做條件相依性檢定(conditional dependence test)，此檢定法可以避免結構式方法(structure form approach)的模型設定問題。當我們控制了相關的外生變數之後，我們發現組織結構型態及保險通路之間是條件不相關的。而此結果和Regan and Tzeng (1999)的發現是一致的，但卻和Baranoff and Sager (2003)及Kim et al. (1996)是不一致的。

In general, there are four types of organizational forms in the property liability insurance industry which are as follows: stock, mutual, reciprocal, and Lloyds. Organizational forms choice of insurers is driven by the differential relative advantages for themselves under its different conditions. Two essays are discussed in this dissertation: (1) Essay 1 we discuss the demutualization and demand for reinsurance for U.S. Property-Liability insurance industry. (2) Essay 2 we discuss the relationship between organizational forms and distribution channels for U.S. Property-Liability insurance industry. Essay I investigates whether U.S. property-liability insurers change their demand for reinsurance after demutualization. We find that converting insurers decrease the demand for reinsurance from non-affiliated reinsurers, but increase the demand for reinsurance from affiliated reinsurers after the conversion. One possible explanation is that converting insurers may treat reinsurance to affiliated reinsurers as risk retention rather than risk transfer so that they can reduce reinsurance cost. Our empirical results show that the overall demand for reinsurance of converting insurers is not statistically different after the conversion. One other interesting finding is that converting insurers increase demand for reinsurance from non-affiliated reinsurers before conversion. Essay II examines how do property liability insurance companies choose their organizational form and distribution channel? Prior studies have not yet provided a consistent conclusion. In this paper, we propose a reduced form approach to reexamine the relationship between organizational forms and distribution channels in the insurance industry, using cross-sectional data pertaining to U.S. property liability insurance companies in 2004. We adopt a conditional dependence test, which can overcome the sensitivity problem of the structure form setting. The results show that after we control for all explanatory variables, the relationship between organizational forms and distribution channels is conditionally uncorrelated. The result is consistent with Regan and Tzeng (1999); but do contradict to Baranoff and Sager (2003) and Kim et al. (1996).