The effect of excessive confidence, optimism, and herd behavior on the investment decision-making process - an applied study in the Iraqi stock market

Authors

  • Maitham Rabee Hadi Al-Hasnawi
  • Ali Ahmed Faris

Keywords:

herd behavior, ,investment decision-making process, the Iraqi stock market

Abstract

The analysis and interpretation of changes in asset prices in financial markets,
has adopted a long period of time on the theories of traditional financial
adopting assumptions that rational investors in these markets and the difficulty
of achieving abnormal profits or superiority in the market in light of the
availability of information to all and uniformity in the interpretation of this
information by investors . But the new entrance in a financial behavioral finance
has proved not as rational investors like traditional financial say and there are
many deviations from rational behavior to them when making the decision
because of the suffering of some of the cognitive and psychological biases that
affect the decision-making process. Hence the study was based on the problem
represented investors in the stock markets suffering from cognitive biases that
may lead them to increases the risk when they making decisions without
adequate compensation for the return. The study tried to show the role played
by biases overconfidence and herd behavior and Over optimism in the decision-
making process for investors in the stock market. The study adopted a
questionnaire to measure these biases and conducted on a sample of investors in
the Iraqi\'s stock exchange amounted to 107 from investors. Statistical methods
were used to help the researcher to detect the presence of these biases and their
impact on the decision-making process. The study found that excessive
confidence and herd behavior and excessive optimism statistically significant
effect on the decision-making process dimensions consisting of trading volume
and the level of diversification and the attitude toward risk.

References

A. Books

- Dent, Peter& Patreck, Michael& Xu, Ye, "Real Estate Property Market

and Sustainable Behavior", Rout ledge, New York, 2012.

- Field, Andy,"Discovering Statistics Using SPSS",3rd ed, SAGE

Publication Ltd., 2009.

- Hede, Peter, "Financial Decision-Making & Investor Behavior",

Bookboon.com,2012.

- Hirshey , Mark & Nofsinger , John , " Investments :Analysis and

Behavior " 2nd ed , McGraw – Hill Irwin 2010 .

- Jordan, Bradford D. & Miller , Thomas , " Fundamental of Investment "

th ed , McGraw – Hill Irwin 2008 .

- Klein, W. M., & Weinstein, N. D. "Social comparison and unrealistic

optimism about personal risk". In B. Buunk & F. X. Gibbons (Eds.),

"Health, coping, and well being: Perspectives from social comparison

theory", Mahwah, NJ: Erlbaum, 1997.

- Levy , Haim & Post ,thievery " Investment ". Prentice Hall 2005 .

- Mayo , Herbert B., "Introduction to Investment " 10th, South-Western,

International Edition, 2011 .

- Pompeian, Michael M. " Behavioral Finance and wealth management " .

John Wiley. & Sons', 2006.

B. Periodicals

- Abele, Andrea, & Hermer, Petra, "Mood influences on health-related

judgments: Appraisal of own health versus appraisal of un-healthy

behaviors", European Journal of Social Psychology, Vol. 23, No. 6, 1993.

- Barber , Brad m., and Odean , Terrance." Boys will be Boys : Gender ,

Overconfidence and common Stock Investment", The Quarterly Journal

of Economics, Vol. 116, issue 1,2001.

- Barber, Brad M .,and Odean , Terrance, "Trading is Hazardous to Your

Wealth: The Common Stock Investment Performance of Individual

Investors", Journal of Finance, Vol. 55, Issue 2, 2000.

- Bracha, Anat & Brown, Donald J., "Active decision making: A theory of

optimism bias" ,Games and Economic Behavior, Vol. 75, No. 1, 2012.

- Brown, Gregory& Cliff, Michael, "Investor Sentiment and Asset

Valuation", The Journal of Business, Vol. 78, No.2, 2005.

- Chira, Inga&Adams,Michael& Thornton, Barry,"Behavioral Bias Within

the Decision Making Process", Journal of Business& Economics

Research, Vol. 6, No.8, 2008.

- Clarke, Roger G.& Statman, Meir, "The DJIA Crossed 652230", Journal

of Portfolio Management, Vol. 26, No. 2, 2000.

- Devenow, Andrea& Welch, Ivo. "Rational herding in financial

economics", European Economic Review, Vol. 40, No. 3, 1996.

- Gervais, Simon& Odean, Terrance, "Learning to be Overconfidence",

The Review of Financial Studies, Vol. 14, No. 1, 2001.

- Helweg-Lasen, Marie& Shepperd, James A., "Do Moderators of the

Optimistic Bias Affect Personal or Target Risk Estimates? A Review of

the Literature", Personality and Social Psychology Review, Vol. 5, No. 1,

0- Kahnman, D., & Tversky, A.,"Prospect Theory:an analysis of Decision

Making Under Risk", Econometrica, Vol. 47, no. 2, 1979.

- Klar, Yechiel& Medding, Aviva & Sarel, Dan, "Nonunique

invulnerability: Singular versus distributional probabilities and

unrealistic optimism in comparative risk judgments",Organizational

Behavior and Human Decision Processes,Vol. 67,No.2, 1996.

- Lewellen, Wilbur G.& Lease, Ronald c.& Schalarbaum, Gary G.,

"Pattern of Investment Strategy and Behavior Among Individual

Investors", Journal of Business, Vol. 50, No. 3, 1977.

- Lin, Huei-Wen, "How Herding Bias could be derived from Individual

Investor Types and Risk Tolerance?", World Academy of Science,

Engineering and Technology, Vol. 66, No. 1, 2012.

- Lovallo. Dan& Kahhneman, Daniel, "Delusions of Success. How

Optimism Undermines Executive Decisions", Harvard Business Review,

Vol. 81, No. 7, 2003.

- Lu, Thomas, "Herd Behaviour, Bubbles and Crashes", The Economic

Journal, Vol. 105, No. 431 1995.

- Odean, Terrance, "Do Investors Trade Too Much", American Economic

Review, Vol. 89, No. 5, 1998.

- Olsen, Robert A., "Desirability Bias Among Professional Investment

Managers", Journal of Behavioral Decision Making, Vol. 10, No. 1, 1997.

- Price, Paul C.& Pentecost, Heather C.& Voth, Rochelle D., "Perceived

Event Frequency and the Optimistic Bias: Evidence for a Tow-Process

Model of Personal Risk Judgment", Journal of Experimental Social

Psychology, Vol. 38, No.3, 2002.

- Scheinkman, Jose& Xiong, Wei, "Overconfidence and Speculative

Bubbles", Journal of Political Economy, Vol. 111, No. 6, 2003.

- Weinstein, Neil D., "Unrealistic Optimism About Future Events" Journal

of Personality and Social Psychology, Vol. 39, No. 5, 1980.

C. Internet

- Berg, Nathan, "Finance, Psychology, Economics and the Design of

Successful Institutions", Economic Globalization & The Choise of Asia,

Shanghai Forum, 2005.

- Campenhout, Geert Van& Verhestraeten, Jan-Francies, "Herding

Behavior among Financial Analysts: a literature review", Hub Research

Paper 2010/39 , 2010.

- Chandra, Abhijeet, "Decision Making in the Stock Market:

Incorporating Psychology with Finance", MPRA,

hppt//mpra.ub.uni.muenchen.de, 2008 Komulainen, Tuomas, " Currency

Crises in Emerging Markets: Capital Flows and Herding Behavior",

Discussion Papers,No 10, Bank of Finland, Institute for Economies in

Transition, 2001.

- Chang, Sheng-Kai, " Herd Behavior, Bubbles and Social Interactions in

Financial Markets", Studies in Nonlinear Dynamics & Econometrics,

- Dargham, Nathalie Abi Saleh, "The Implication of Behavioral

Finance",Chargee Denseigment FGM, 2007.36- Dittrich, Dennis& Guth, Werner& Maciejovsky, "Overconfidence in

Investment Decisions- An Experimental Approach",JEL

Classification:C910 D800, D840,G110, 2001.

- Elan, Seth," Behavioral Patterns and Pitfalls of U. S. Investors ", A

Report by the Federal Research Division, WWW.Ioc.gov./rr/frd,2010.

- Farrell, Paul, "Investors are Their Own Worst Enemy", 2003.

- Fuller, Russel J., " Behavioral Finance and Source of Alpha", 2000.

- Healy, Andrew& Offenberg, Jennifer, "Overconfidence, Socail Groups,

and Gender: Evidence from the LAB and Field", JEL Code C90, C93,

Lo,J16, April, 2007.

- Garven , James R. & Hilliard, James I. , "Optimism Bias and the

Demand for Health Insurance", 2013.

- Holden, Karen, "Theories of Human Behavior and Emotions: What They

Imply About the Financial Behavior of Vulnerable Populations", Center

of Financial Security, CFS, 2010.

- Lutje, Torban& Menkhoff, Lukas, "What Drive Home Bias? Evidence

from Fund Managers' Views", Working Paper, University of Hanover,

ISSN, 2004.

- Mayraz,Guy,"The optimism bias: experiment and model",University of

Melbourne, 2013.

- Montier, James,"Global Equity Strategy", Dresdner Kleinwort, 2002.

- Park, Beum-Jo, " Herd Behavior and Volatility in Financial Markets",

- Sharot, Tali, "The Optimism Bias", Time News Feed, 2011.

- Survey System, Creative research System, (www.surveysystem,com).

- Tversky, Amos, "The Psychology of Risk", Association of Investment

Management and Research, 1990.

- Weinberg, Bruce A., "A Model of Overconfidence", Working Paper,

Institute for the Study of Labor, www.ECONSTOR.EU, 2009.

Published

2025-01-15

How to Cite

ميثم ربيع هادي الحسناوي, & علي احمد فارس. (2025). The effect of excessive confidence, optimism, and herd behavior on the investment decision-making process - an applied study in the Iraqi stock market. Iraqi Journal for Administrative Sciences, 10(39), 104–126. Retrieved from https://mail.journals.uokerbala.edu.iq/index.php/ijas/article/view/2991