portfolio is under diversified” (Gr

portfolio is under diversified” (Grinblatt and Keloharju, 2001). These investors
mostly select the stocks that make up their portfolio on the basis of geographical or
professional proximity to them. Also the urban investor chooses to concentrate his
portfolios in close stocks (Goetzman et al., 2004).
The existence of ambiguity and difficulties to understand the unfamiliar stocks
accounts for the implication of the familiarity and availability biases in the portfolio
diversification:
H4. The familiarity and availability biases will negatively influence the portfolio
diversification.
2.5 Overconfidence
Individual investors might take correlations into account, but they underestimate their
strength. For example, investors who are overconfident about the correctness and the
pertinence of their information may analytically exaggerate correlations among stocks
and because they prefer to own a portfolio with lower level of diversification. The level of
diversification is also interrelated with investment preferences that are reliable with
overconfidence. Investors could shape the portfolio diversification sense of overconfidence
in their investment abilities. When formulating their investment decisions, they can
extend an erroneous sense of control because they are directly occupied in the investment
process and make their individual choices as an alternative of relying on others.
An illusion of control could generate an inappropriate level of overconfidence.
Overconfident investors might prefer not to diversify because they might wrongly
suppose that they will receive larger performance through active trading:
H5. The overconfidence bias will negatively influence the portfolio diversification.
3. Methodology
3.1 Questionnaire design
The survey consists of three sections. The first section contains some information
related to the background of the respondents. The respondents are asked questions
about their portfolio diversification, age, gender, income, employment status, trading
experience. The second section is about determinants of psychological effect on
investors’ decision-making (see the Appendix). Responses to each of these items were
elicited on five-point scales ranging from 5 ¼strongly agree to 1 ¼strongly disagree.
The respondents are required to answer all the questions based on their opinions
and perceptions. The last section aims to assess the financial literacy level. The
respondents are required to answer 11 question exam-types (Al-Tamimi and Kalli,
2009; Rooij et al., 2011).
3.2 Sampling and data collection
Our empirical study is based on qualitative research. We use a questionnaire as a
method of data collection. The questionnaire was available online and this permitted us
to ensure confidentiality and privacy of the data provided by the respondents. The data
include over 300 individual (small) Tunisian investors currently trading and managing
directly their investments in the Tunisian stock exchange.
The surveyed respondents had to be over 18. In terms of response rates, a traditional
response rate measure could not be computed because online surveys are administrated
in a different manner from standard telephone and paper surveys. Only 256 individual

Hasil (Bahasa Indonesia) 1:

Portofolio Diversifikasi di bawah"(Grinblatt dan Keloharju, 2001). Investor inisebagian besar memilih saham yang membuat portofolio mereka atas dasar geografis ataudekat profesional mereka. Juga perkotaan investor memilih untuk berkonsentrasi nyaportofolio di dekat saham (Goetzman et al., 2004).Keberadaan ambiguitas dan kesulitan untuk memahami saham asingmenyumbang implikasi dari keakraban dan ketersediaan bias dalam portofoliodiversifikasi:H4. Bias keakraban dan ketersediaan akan negatif mempengaruhi portofoliodiversifikasi.2.5 lebihanInvestor individu mungkin memerlukan korelasi ke account, tetapi mereka meremehkan merekakekuatan. Sebagai contoh, investor yang terlalu percaya diri tentang kebenaran dankebenaran informasi analitis mungkin melebihkan korelasi di antara sahamdan karena mereka lebih memilih untuk memiliki portofolio dengan tingkat yang lebih rendah dari diversifikasi. Tingkatdiversifikasi juga saling berkaitan dengan preferensi investasi yang handal denganlebihan. Investor dapat membentuk rasa diversifikasi portofolio lebihandalam investasi kemampuan mereka. Ketika merumuskan keputusan investasi mereka, mereka dapatmemperpanjang rasa kontrol salah karena mereka langsung sibuk di investasiproses dan membuat mereka pilihan individu sebagai alternatif mengandalkan orang lain.Ilusi kontrol dapat menghasilkan tingkat tidak pantas lebihan.Overconfident investors might prefer not to diversify because they might wronglysuppose that they will receive larger performance through active trading:H5. The overconfidence bias will negatively influence the portfolio diversification.3. Methodology3.1 Questionnaire designThe survey consists of three sections. The first section contains some informationrelated to the background of the respondents. The respondents are asked questionsabout their portfolio diversification, age, gender, income, employment status, tradingexperience. The second section is about determinants of psychological effect oninvestors’ decision-making (see the Appendix). Responses to each of these items wereelicited on five-point scales ranging from 5 ¼strongly agree to 1 ¼strongly disagree.The respondents are required to answer all the questions based on their opinionsand perceptions. The last section aims to assess the financial literacy level. Therespondents are required to answer 11 question exam-types (Al-Tamimi and Kalli,2009; Rooij et al., 2011).3.2 Sampling and data collectionOur empirical study is based on qualitative research. We use a questionnaire as amethod of data collection. The questionnaire was available online and this permitted usto ensure confidentiality and privacy of the data provided by the respondents. The datainclude over 300 individual (small) Tunisian investors currently trading and managingdirectly their investments in the Tunisian stock exchange.The surveyed respondents had to be over 18. In terms of response rates, a traditionalresponse rate measure could not be computed because online surveys are administratedin a different manner from standard telephone and paper surveys. Only 256 individual