I. IntroductionAccording to Baker and Nofsinger (2002), the conventional financial theory is based on the presumption that markets are efficient and investors tend to behave in a rational way. They extend the discussion arguing that every model ignores the fact of the human behaviour involved in the decision taking and investment approach people go through. They argued that individual and social psychological biases make a difference in investors’ returns since they do not tend to behave rationally. In fact, Shefrin (2000) stated that these biases may expose investors’ wealth to a serious risk and possible unexpected losses given by lack of diversification. This situation has brought economic research attention in order to understand the market behaviour and define better realistic model.
As result of this the following question arises: Are investors’ lack of diversification due to psychological biases? In this essay we will expose some ideas behind the topic. In our endeavour we will give special attention to the phenomenon of Home Bias puzzle as a way to answer our question. Home Bias is known as investors’ preference to overweight domestic securities in their portfolios (Grinblatt and Keloharju, 2001). To devise what causes the phenomenon may lead to a conclusion about the relevance of psychological biases to affect lack of diversification.
In this essay we will first expose the common approaches given to explain how Home Bias is given and how it relates to a lack of diversification. Next, we will extend the topic bringing some related empirical evidence. Later, we state possible future research and finally we present some conclusions.
II. Home Bias as an Explanation for Lack of DiversificationOn the grounds of rational investment, diversification is a proven way to avoid risk and lock a bigger probability of success. Spreading the risk among several securities brings the chance to achieve a combination of higher return with low risk. Diversification strategy is so important, that many financial literatures have taken the aim to analyze why investors do not follow this rational behaviour in order to secure the best possible results.
Home Bias is the preference of the investor to acquire domestic securities with some sense of familiarity. The phenomenon is present when investors overweight with local securities their portfolio. This overweight brings within a lack of diversification. For this essay purpose, we will understand lack of diversification as the deficiency of investors to allocate foreign securities and the excessive weight they give to domestic securities in their investment portfolios. There is an avid debate to understand how the Home Bias puzzle is given. There are two current attempts of explanation: the objective perspective and the subjective perspective. Objective perspective stands for all those factors related to market framework such as regulation and facilities. Subjective perspective pursues a psychological approach to the topic. Each of them makes an effort to find an answer to Home Bias essence as the source of the lack of diversification in investment portfolios from opposite standing points. (French and Poterba 1991)
A. Objective PerspectiveThis explanation advocates to those actions based on rational facts that may limit diversification. We will mainly focus on Coval and Moskowitz (1999) studies in Institutional Constraints. Institutional Constraints point out all the regulations boundaries such as government restrictions, foreign taxes and transactions costs which may lead to concentration of domestic securities in investments portfolios. This argument mainly states that investor diversifying capacity is constrained by the obstacles found to acquire stocks abroad of their domestic market, pushing him to rely on domestic securities.
French and Poterba (1991) shed some light about the real impact of these constraints to explain the lack of international diversification. Institutional Constraints are supposed to limit foreign stocks holding. Nevertheless, they argued that these constraints are not the best approach to explain the low level of international allocation equity because they just define the frame in which investors interact. The result of their findings showed that Institutional Constraints are not so different among them. To address this state, we will mention Tax Burden and Transaction Costs.
They found that the actual Tax Burden among countries with big stock markets are very similar (such as: United Kingdom, United States and Japan). Even though, they added that investors’ home country may accredit the foreign withholding taxes as part of the domestic taxes. So, there is no actual difference to push investors to select domestic securities. (French and Poterba, 1991)
Transaction Costs are proven to be linked to the liquidity of the market. This means that for cases of markets with great liquidity (i.e. New York Stock Exchange) the transaction costs are proven to be lower. In theory, a rational investor may choose the market with lower costs as one of the top criteria. Thus, Transaction Costs are not an issue to diversify portfolios. (French and Poterba, 1991)
Furthermore French and Poterba (1991) questioned if explicit limits on cross-border investment may affect the weight of a portfolio. In practice this does not seem to be the case. For example, they explained the French case in which a foreign investor may be able to hold up to 20% of any firm without any authorization of the Ministry of Economy and Finance.
Therefore, given the past considerations we cannot suggest the objective approach in its Institutional Constraints form to explain the lack of diversification in investment portfolios under the Home Bias scope.
B. Subjective PerspectiveWe will now focus on the subjective approach describing the main psychological biases that investors experiment. Baker and Nofsinger (2002) argue that investors put together their ideas and feelings to decide what and how to invest. They establish two big categories to classify these psychological biases: how investors think and how investors feel. We will explain more relevant aspects of both areas to show how they demonstrate with a lack of diversification under Home Bias point of view.
B.1 How Investors' thinkRegarding investor’s thinking, Baker and Nofsinger (2002) stated two main reasons for no-diversification related to Home Bias: Familiarity Bias and Mental Accounting.
Familiarity Bias explains that people are more likely to deal with known facts rather than to discover new elements. They rely more on familiar facts because they tend to believe this will avoid undesired surprises and bigger risk. Therefore, they may lead investors to give excessive weight to domestic securities because they generate some sympathy with those companies who have some affinity with their core business. This can explain why household investors tend to invest in those companies they are working for as Grinblatt and Keloharju (2001) suggested.
Furthermore they explain the Mental Accounting is the propensity to overlook interaction between several assets. Shefrin and Statman (2000) found that Mental Accounting distorts the perception of risk because investors are not able to correlate several investments at the same time. Thus, Baker and Nofsinger (2002) pointed out that this wrong perception may lead the investor to choose a wrong or poor diversification. It seems easier for investors to access local news rather than monitor several foreign markets particularities.
B.2 How Investors' feelMoving now to the fact of investor feelings, Baker and Nofsinger (2002) established just the Attachment Bias as the feeling that may affect investment diversification. The Attachment Bias is an emotional linkage of the investor to a security. This leads the investor to concentrate their investment in those securities with some affinity related to his idiosyncrasy such as language or cultural background (Grinblatt and Keloharju, 2001).
Therefore, the psychological approach presents itself as a good option to explain Home Bias as a cause of lack of diversification. To complement this theoretical explanation, we will discuss in the following section some related empirical papers.
III. Empirical EvidenceAmong the latest empirical evidence to support the Home Bias as one of the Psychological Bias expresions of non-diversification in investment portfolios we found the work of Grinblatt and Keloharju (2001). They followed a study in Finland in order to find the presence of Home Bias puzzle in the equity market. They ran an analysis based on the evaluation of three psychological aspects: perception of distance from investor to the company, cultural empathy and language affinity. After, applying some ratios and regression analysis separately for each area they found that these three factors affected investments relation in proportion with the investors’ sophistication. Thus, household investors and less savvy institutions were more affected by these criteria than sophisticated investors. These results are good empirical evidence of Mental Accounting bias. The preference of an investor for companies with the same cultural background and the same language is a good example of Familiarity Bias and Representation Bias. Investors’ sophistication findings are a reflection of the statement given by French and Poterba (1991) which talks about the difficulty of the investor to understand risk exposure and expected returns due to a lack of knowledge.
In addition to these findings, Coval and Moskowitz (1999) found that the United States investors showed a bias to invest in firms geographically closer. Moreover, United States investors held more than 90% of local securities in their portfolios giving few chances to foreign securities. The same phenomenon is shown by French and Poterba (1991) who demonstrate that in other countries the proportion of domestic securities is bigger. This is the case of United Kingdom (92%), Germany (79%), France (89.4%) and Japan (95.7%).
IV. Further ResearchNevertheless, there are several areas available to extend the work done. To prove the actual relation of culture, language and distance effect on investments, Grinblatt and Keloharju (2001) argued that the same analysis should be done in bigger and more complex stock market (i.e. FTSE100). These markets offer the possibility to explore the relation of investors when they are exposed to a more heterogeneous and dynamic environment.
French and Poterba (1991) extend the invitation to study mutual funds as proxy of this behaviour. The domestic diversification of mutual funds has been proven but there is no evidence they tend to diversify with foreign securities.
Baker and Nosinger (2002) argued a lack of information to prove the real impact of Psychological Bias for portfolio diversification with more empirical analysis. They also extend the challenge to adapt experimental economics with psychological methods in order to find an answer for the incidence of psychology in investment decisions and the utility of surveys to measure current investors’ behaviour.
V. ConclusionHome Bias puzzle is a phenomenon that leads investors to overweight domestic securities in their investment portfolios. It tries to explain why investors do not diversify their portfolios due to psychological biases that lead them to higher risk exposure. The topic has brought the attention of several researches in the financial areas. (Grinblatt and Keloharju, 2001)
There is some evidence investors are not diversifying enough due to the Home Bias phenomenon. French and Poterba (1991) found that major trading countries overweight their portfolios with domestic securities. Thus, they established two explanations to the lack of diversification: Institutional Constraints and Psychological Bias. Institutional Constraints stands over an objective evaluation of trading frame, but is it proven it does not affect the lack of diversification and does not push the investor to fall in Home Bias. On the other hand, Psychological Bias suggests that investors’ behaviour is pushed by subjective criteria and produce Home Bias phenomenon. This work is extended by Baker and Nofsinger (2002) categorizing some Psychological Bias that may affect investors’ criteria.
In addition, Coval and Moskowitz (1999) followed and empirical analysis for the United States and demonstrated diversifying decisions were affected by geographic factors. Later on, Grinblatt and Keloharu(2001) showed Finnish investors were biased to choose their securities by language, culture and proximity criteria.
Therefore, there is evidence supporting that investors do not diversify enough with international securities because the effect of Home Bias as a psychological bias.
Nevertheless, researchers agree that investigation can be extended with more empirical analysis and a possible mix of psychological methods and experimental economics. (French and Poterba, 1991, Grinblatt and Keloharju, 2001and Baker and Nosinger, 2002)
ReferencesBaker H. K. and Nofsinger J. R. (2002) “Psychological biases of investors” Financial Services Review 11: 97-116
Joshua D. Coval and Tobias J. Moskowitz, (1999) “Home Bias at Home: Local Equity Preference in Domestic Portfolios” Journal of Finance, American Finance Association, vol. 54(6), pages 2045-2073
French, Kenneth & James M. Poterba (1991) "Investor Diversification and International Equity Markets” American Economic Review 81, 222-226
Mark Grinblatt M. and Keloharju (2001) “How Distance, Language, and Culture Influence Stockholdings and Trades” Journal of Finance, American Finance Association, vol. 56(3), pages 1053-1073, 06
Shefrin, H. (2000) “Beyond greed and fear: understanding behavioural finance and the psychology of investing” Harvard Business School Press.
Shefrin, H. and Statman, M. (2000) “Behavioural portfolio theory” Journal of financial and Quantitative Analysis, 35 (2), 127-151