隨著金融財務工程演進，透過精密電腦運算，衍生性金融商品不斷推陳出新，提供銀行及投資人避險及投資等多元管道。但是，水能載舟亦能覆舟，次貸風暴的發生，主要原因正是銀行利用衍生性金融商品過度從事槓桿及投機交易，其面臨風險已非區區資本適足率8%所能承受，也因此造成全球銀行的倒閉風暴。 本研究主要藉由了解次順位債券的特色及功能，次順位債券的訂價與評價，以及透過台灣、中國大陸、及美國等三個國家發行次順位債券情形，和各國主管機關與巴塞爾資本協定對次順位債券監理與規範，分析探討銀行發行次順位債券的目的、影響次順位債券發行成本的因素、投資人對於次順位債券的投資行為、以及次順位債券對於銀行資本管理的影響。 研究顯示，銀行的財務結構、信用評等、及資本適足率與發行次順位債券的風險溢酬，呈現顯著的反向關係；逾期放款比率及信用價差與發行次順位債券的風險溢酬，呈現顯著的正向關係。銀行風險承擔能力的良窳決定次順位債券的發行成本，次順位債券風險溢酬的高低，也成為投資人判斷投資標的資訊來源之一。銀行可藉由發行次順位債券提高資本適足率，作為吸引損失準備；銀行信用評等越高、財務結構越健全，發行次順位債券的機率也越高。投資人可藉由銀行信用價差及次順位債券發行利率做為投資判斷的資訊，進而發揮間接的市場制約功能，輔助主管機關的金融監理。 / Several recent studies have recommended greater reliance on subordinated debt (SND) as a tool to discipline bank risk taking. Some of these proposals recommend using sub-debt yield spreads as triggers for supervisory discipline under prompt corrective action (PCA).This yield spread is considered to be a good measure of bank risk, as the holders of SND absorb the first loss in the case of a bank failure. Currently such action is prompted by capital adequacy ratio measures. Evidence from previous research suggests that yield information may be a better predictor of bank problems. This paper empirically analyzes potential costs and benefits of using SND signals to effect bank capital management and consideration should be given to using spreads to complement supervisory discipline. The goal of this study is to provide a comprehensive review and evaluation of purpose and potential of SND proposals and to present a regulatory reform proposal that incorporates what we believe are the most desirable characteristics of SND.

本文立基於Merton(1974)或有求償權評價法及Leland(1994)內生破產資本結構模型上，加入次順位債券的考量，建立一個連續時間資本結構分析模型，量化的資本結構可作為企業融資之決策依據。內生破產行為與風險移轉行為都是股東與債權人之間可能產生的代理問題，本文的模型不但分析這兩種代理問題，更計算其所產生的代理成本。由模擬的結果發現內生破產成本雖然不大，但是其對無風險利率及公司非槓桿價值的波動度卻是非常的敏感。在本文的模型下，只要債務契約不能重新訂立，次順位債券的發行永遠都會降低優先債務的價值。在本模型中次順位債券的風險貼水比優先債券的風險貼水高；但是本文發現不管是優先債券或是次順位債券的風險貼水，當公司接近宣告破產時，公司非槓桿價值的波動度對兩種債券風險貼水的影響出現高風險低報酬的現象，可能的解釋理由如下：當公司接近宣告破產時，公司非槓桿價值波動度的增加使破產可能性提高，進而使風險貼水減少的間接力量大於波動度增加直接使風險貼水上升的力量。 / Based on Merton(1974) and Leland(1994), we construct a continuous-time capital structure model with subordinated debt. Quantitative results may serve the guidance of financial policy of the firm. Both endogenous bankruptcy and risk shifting behaviors are the agency problems between the equityholders and debtholders. Based on our model, the agency problems is considered and the agency costs are calculated. From the result of simulation, endogenous bankruptcy agency cost is small but sensitive to the volatility of unlevered asset value of the firm. Under renegotiation-proof, the senior debt is harmed by the issuance of the subordinated debt in our model. The risk premium of the subordinate debt is higher than that of the senior debt is confirmed by the model, however, when the firm is near bankruptcy, the behavior of "high risk high return" of both debts is reversed. The reason for the junk bond behavior may be explained as the negative effect of risk premiums due to the increase of the probability of bankruptcy is higher than the positive effect of the greater risk caused by higher volatility.