本篇論文主要是在探討信用評等、再保險和資本結構三者的相互影響關係，在保險市場，信用評等反映保險公司經營財務狀況的訊息並且提供資訊給投資人以及投保人，因此信用評等會影響保險公司的資金成本與再保險決策；然而再保險需求與資本結構也會影響保險公司的違約風險，因此對於信用評等有很重要的影響。我們認為保險公司的信用評等、再保險需求與資本結構三者是同時被決定的。我們使用1985到2010年間英國壽險的資料並以聯立方程迴歸模型及二階段最小平方法來估計。結果發現使用較多再保險及有較低財務槓桿的保險公司信用評等較高，這是因為再保險能夠幫助減少保險公司的未來損失而較低的財務槓桿降低公司的破產風險；再者，信用評等及財務槓桿對再保險皆有正向關係；最後，符合租用資本假說，再保險的需求增加也會增加保險公司的財務槓桿，然而我們的樣本並不支持信用評等對財務槓桿的影響。

In this study we primarily examine the interaction between credit rating, reinsurance and capital structure. Credit rating can be regarded as a signal in insurance market to reflect the insurance firm’s operating and financial conditions and provide information to investors and policyholders. Therefore, credit rating can affect the cost of capital and reinsurance decisions. At the same time, the use of reinsurance and leverage also affect the default risk and change the rating level assigned by the rating agency. We therefore think these three variables are jointly determined. We use a data set of U.K. life insurance industry from 1985 through 2010 and employ a simultaneous equation model and test it by two-stage least squares. First, we find that insurers use more reinsurance and with a lower level of leverage are more likely to get a higher rating level. This is because reinsurance effectively helps to reduce ceding insurer’s probability of future loss and less leverage decreases the insolvent risk. Then, the results show that both credit rating and leverage have positive effect on reinsurance. Finally, consistent with renting capital hypothesis, the findings indicate that the more demand for reinsurance increase insurer’s leverage, however, the effect of credit rating on leverage is not supported by our sample.

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