Kauppakorkeakoulun julkaisuportaali
Aalto-yliopiston kauppakorkeakoulun gradujen tiedot nyt Aaltodocissa: Aaltodoc-julkaisuarkisto
Kauppakorkeakoulu | Laskentatoimen ja rahoituksen laitos | Rahoitus | 2010
Tutkielman numero: 12226
Debiasing overconfidence of Finnish investment advisors
Tekijä: Perttula, Milla
Otsikko: Debiasing overconfidence of Finnish investment advisors
Vuosi: 2010  Kieli: eng
Laitos: Laskentatoimen ja rahoituksen laitos
Aine: Rahoitus
Asiasanat: rahoitus; financing; behavioral finance; behavioral finance; sijoittajat; investors; sijoitukset; investments; neuvonta; counselling; luottamus; trust
Sivumäärä: 90
Avainsanat: behavioral finance; investment advisors; overconfidence; debiasing


The objective of this thesis is to examine debiasing of three types of overconfidence on investment advisors. These three types of overconfidence are ‘better-than-average’, ‘miscalibration’ and ‘unrealistic optimism’. A controlled field study is carried out to find out if debiasing attempts lower the overconfidence of investment advisors. A basic study is done first to examine the effect of debiasing with a sentence. Furthermore, an extension study is done with another group to further examine the effect of lecture as a way of debiasing.


The data in this study are collected in controlled field surveys. The surveys are carried out for two different groups of people; total 89 investment advisors from two different companies. The participants of the surveys answer a questionnaire which contains both background related questions and questions which test the three types of overconfidence. A random half of the subjects from the first company receive a questionnaire with debiasing attempts and the other half a basic one. The participants of the second company all receive the debiased questionnaire. Overconfidence and the deabiasing effects are studied by comparing the answers from the two random groups with different questionnaires.


This study does show that the investment advisors are biased in two out of three types of overconfidence. However, some of the debiasing methods introduced in this study can lower overconfidence, depending on the type of overconfidence. When studying better-than-average, warning about overconfidence by stating that the subject should keep in mind that other people also see themselves as better than average, can lower confidence. However, warning only works in one of the two questions in this study. Lectures about investor psychology, on the other hand, do work with both of the questions as a debiasing method. Miscalibration–type of overconfidence is neither made better with the statement on the questionnaire to make the intervals bigger nor with the lectures, as debiasing methods. The last type of overconfidence, unrealistic optimism, are the subjects in this study not, on average, suffering of. Nevertheless, the return expectations are still affected by the debiasing method, however, only lectures actually lower the expectations, whereas listing reasons why one might be wrong only makes the expectations higher. Therefore, the best way of lowering overconfidence is lecturing investment advisors about investor psychology covering overconfidence.
Graduja säilytetään Oppimiskeskuksessa Otaniemessä.