Common risk factors in the German stock market

Are returns predictable?

Diploma Thesis from the year 2007 in the subject Business economics - Banking, Stock Exchanges, Insurance, Accounting, grade: 1,3, University of Tubingen, 69 entries in the bibliography, language: English, abstract: This paper develops a multifactor model for explaining the difference in average returns for the German stock market in the period between July 1990 and June 2007. The methodology of Fama and French (1993) is adopted to determine possible common risk factors in that market. Despite the enormous and strong stock markets movements and the high volatility during that period, the three factors RM-RF, SMB and HML seem to be able to capture cross-sectional variation in average returns for portfolios formed on various sorting criteria based on publicly available financial data. In addition, the analysis shows a negative (risk?) premium for small size stocks, which is a surprising result since it contradicts previous studies for the German, but also international markets. For stocks with a high book-to-market value, a strong positive premium is found. This value effect is consistent over time and statistically significant. Positive premiums seem to exist for high E/P and C/P stocks as well. These market anomalies show that returns are indeed predictable in the German market over long time horizons. High BM, E/P and C/P stocks do outperform stocks with low ratios in these categories significantly and consistent over time. However, the evidence in this analysis highlights that the common explanation in rational asset-pricing models of an outperformance due to some economic risk factors that are proxied by HML and SMB must be strongly questioned. Portfolios consisting of value stocks outperform growth portfolios in all possible states of the stock market. This evidence is contradictory to the 'marginal value of wealth' assumption in the rational asset pricing models presented. Additionally, there is a January effect in stock returns which cannot be captured by a risk-based, rational asset pricing model. Thus, the evidence suggests that it is in fact investor irrationality which is causing differences in average returns across stocks. RM-RF, SMB and HML can be described as common factors helping to explain return differences, but it is very likely that it is not underlying economic risk, but investor behavior which is causing the presented market anomalies and return predictability.