Each stock investor has a different personality type, which can be classified into five
personality traits: openness, conscientiousness, extraversion, agreeableness, and neuroticism
(OCEAN). These personality differences affect the behavior of investors in making investment
decisions. The behavior of investors in the investment decision-making process is often
irrational, resulting in decisions that are not optimal. The irrationality is caused by a behavioral
bias that contains elements of psychology and emotion. This study aims to determine whether
personality traits can affect the irrational behavior of stock investors. In particular, two
behavioral biases are influenced by personality traits; availability bias and disposition effect.
This work collected 716 questionnaires from investors with different gender, ages, income,

education, and occupation profiles. The data was analyzed using Partial Least Square-
Structural Equation Modeling (PLS-SEM). It was found that openness, extraversion, and

agreeableness positively influence availability bias and disposition effects. Conscientiousness
only affects the disposition effect, while neuroticism negatively affects the availability bias.
Neuroticism investors have a tendency not to be exposed to availability bias. This type of
personality will not rely on the easily obtained information. On the contrary, investors with
openness, extraversion, and agreeableness make their investment decision based on currently
available information. Investors with openness, extraversion, conscientiousness, and
agreeableness tend to sell profitable stocks as soon as possible and hold stocks that are still
losing. This research is beneficial for investors, investment managers, and stock analysts.