Hedging Systematic Credit Risk with Stock Index Futures

系統性信用風險即倒帳風險，是各個企業和銀行都會面臨的問題，當景氣蕭條時，企業或個人可能無法按時支付本金與利息，此時信用風險的程度提高；相對而言，景氣佳時，不論個人或企業的償債能力均提高，信用風險明顯下降，因此這裡所謂的系統性信用風險其實就是景氣循環風險。本文提出一個相當直覺的觀念來規避系統性的信用風險，既然景氣循環影響了系統性信用風險的高低，我們現在的目的就是要規避景氣循環風險，而股價指數的變化其實就是景氣循環的領先指標，因此我們可以由股價指數或種種總體經濟指標來預測未來的景氣狀態，接著就可以利用買進或賣出股價指數期貨的方式來規避景氣循環風險。本文以八個國家作實證研究，包括了台灣、美國、英國、法國、日本、瑞士、墨西哥、澳洲等已開發國家及開發中國家，並選取實質GDP成長率以及工業生產指數作為景氣循還的指標，進行OLS簡單迴歸、移動迴歸、二次迴歸、以及Downturn下的OLS簡單迴歸。實證結果發現：台灣、日本、澳洲與墨西哥的股價指數期貨報酬率與實質GDP成長率呈正向關係，且具預測能力，其t-value均為顯著，故適用本文所提出的避險概念。而美國與英國在大部分的時期，股價指數期貨報酬率與實質GDP成長率呈正向關係，因此股市還算具有預測景氣循環的能力，仍適用本文所提出的避險概念。至於法國與瑞士的股價指數期貨報酬率與實質GDP成長率呈負向關係，股市無法作為景氣循環的領先指標，其t-value均不顯著，故不適用本文所提出的避險概念。Systematic credit risk is default risk, which is a problem any enterprises and banks may face. When the economy is in the downturn, enterprises or individuals may not afford to pay the principal and interests on time. At this moment, the probability of the occurrence of the credit risk is very high. In contrast, when the economy is in the upturn, enterprises and individuals’ ability of paying back the debt is lifted. Apparently, the probability of the occurrence of the credit risk is low at this moment. Therefore, the so-called systematic credit risk is business cycle risk.This thesis presents a direct and simple concept to hedge the systematic credit risk. Since the business cycle affects the level of systematic risk, our purpose now is to hedge the business cycle risk. Besides, from the previous surveys, the change of stock market is a leading index of business cycle. As a result, we can predict the economy situation in the future by stock index and hedge the business cycle risk by purchasing or selling stock index futures contracts in advance.This thesis do empirical study depended on the data of eight developed or developing countries, inclusive of Taiwan, U.S.A., England, France, Japan, Switzerland, Mexico, and Australia. We choose real GDP growth rate or industry product index as business cycle index, and then run simple OLS, rolling regression, quadratic regression, and simple OLS under downturn to get the hedge ratio and its t-value.The empirical results are as follows:1、The relationship between the rate of return of stock index futures and real GDP growth rate in Taiwan, Japan, and Australia is positive. In other words, the rate of return of stock index futures can be a predictor of real GDP growth rate and the t-value of the hedge ratio is significant. Therefore, we can hedge the systematic credit risk in these countries by selling stock index futures contracts in advance.2、In most periods, the relationship between the rate of return of stock index futures and real GDP growth rate in U.S.A. and England is positive. Therefore, the change of stock market still can predict the business cycle and we can apply the hedge concept in this thesis in the two countries.3、The relationship between the rate of return of stock index futures and real GDP growth rate in France and Switzerland is negative. In other words, the change of stock market can’t early reflect the phenomenon of business cycle and the t-value of the hedge ratio is not significant. As a result, the hedge concept presented in my thsis is not applicable in these countries