فصلنامه مطالعات تجربی حسابداری مالی
پیاپی 39 (پاییز 1392)

Herding behavior is among the most noticed biases in behavioral finance. This bias implies that investors unknowingly neglect personal information and analyses; instead they tend to follow other investors or the whole market. Using Tehran Exchange stocks transactions data, this study empirically examines herding behavior in this market. Two models based on cross-sectional deviation of stock returns and another model based on beta in state-space structure are utilized in our research. The sample covers 21,112 weekly returns and transaction volumes observations from April 2005 to April 2011. Our findings indicate that participants often lack independent investment decisions; i.e. they prefer following other investors’ decisions to taking an independent approach. This confirms that herding behavior exists in Tehran Stock Exchange. Moreover, evaluating comparative power of our three models suggests that the model based on beta is more powerful in explaining herding behavior than the other model.

The purpose of this research is the consideration of the relation between supplier's and customer's bargaining power and accounting conservatism. In this research it is expressed that in order to protect their interest, the suppliers and customers try to appreciate Firms to increase conservatism in financial reporting. Instead, the Firms try to withstand to demand of suppliers and customers for accounting conservatism, because of inappropriate image of company shown by conservatism. If the company has more power of bargaining than suppliers and customers, then it will have less sensitivity against supplier's and customer's demand of accounting conservatism. Otherwise the company has to use more conservatism policies in its financial reporting. Empirical analysis uses data from the 1826 Firms-year during the period 1381 to 1390 indicate that there are significant positive relationship between the bargaining power of suppliers and customers with accounting conservatism. Also, the results revealed, the company's dependence on raw materials and the quality of after-sale services durable goods producers to reduce the bargaining power of the company and increase the conservatives in the aftermath of the financial reporting will have; In addition, the company's industrial activities that have high barriers to entry, the bargaining power of firms increases and decreases the level of conservatism of financial reporting. Overall, the results indicated that the company's suppliers and customers who have higher bargaining power, Companies have the ability to dictate the terms of trade, and in this situation, conservative accounting firms to demand from them will be more sensitive.

This research follow up the relation between conservatism and short term abnormal returns of IPOs in Tehran Stock Exchange and also infusing of asymmetry information among beneficiaries in IPO’s procedure in mentioned relation. The results of regression analysis for companies which their stocks offered in Tehran Stock Exchange for period of 1382 to 1391 shows the relation between conservatism and short term abnormal returns of IPOs is meaningful and reverse. In the other word by increasing the level of conservatism, verifiability of presented information has been gone up and by decreasing of asymmetry information among beneficiaries in IPO’s procedure; short term abnormal return of this stock will be decrease. In the other hand the relation between conservatism and short term abnormal returns of IPOs in companies with high level of asymmetry information is stronger than companies with low level of asymmetry information.Also the results of research show the IPOs’ stocks have created averagely 26.07% Initial normal returns and 19.61% Initial abnormal returns (Returns adjusted by Market Portfolio) that confirmed the under pricing in Tehran Stock Exchange according to researchers in other countries.

As the amount of dividend is one of the effective and final factors in investor decision making, dividend policy of companies that decides the amount of dividend, could play a very important role in making decisions. Dividend policy is reciprocally influenced by individual behavioral specifications. These specifications have an extensive coverage from which a few has been selected for this study. By measuring limits of patience and loss aversion of shareholders this study is trying to analyze their relations with companies’ dividend policy.The necessary data for trial assumptions, belonging to 77 companies for a period of 5 years between 1386-90, has been collected from Tehran stock exchange data base. the relation between variables have been examined by testing correlation coefficients and multiple regressions. Study shows there is no meaningful relation among percentage of dividend and stockholders patience, based on effecting date of dividend payment measurement and the amount of adjusted earnings per share measurement of companies accepted in Tehran stock exchange. On the other hand relation between dividend ratio percentage and measurement of companies profit growth is meaningful but to the contrary. So based on index of companies profit growth, a meaningful relation exists between payable dividend policy and loss aversion of shareholders. According to the market risk measurement, has no meaningful relation between loss aversion and dividend policy.

This article is seeking to provide a proper model for selecting portfolio. To do that, first we should studied literature to discover suitable criteria. Then we have used a questionnaire for determining criteria's relationships to rank them. Managers of mutual fund asked to answer this questionnaire. To determine these relationships, we used DEMATEL technique. After that, these criteria were ranked by using Analytic Network Process. Thus, 50 companies with more cash in market between1385-1389 were chosen to assess these criteria. These companies were ranked by TOPSIS and a portfolio selected with the top 30. Return of portfolio consist of 30 companies had compared with the average return of portfolio consist of 50 stock and was shown by Sharp Index that the proposed model can be useful for managers in their portfolio selection.

Information uncertainty has been an old topic in finance literature. Information uncertainty means ambiguity about a firm’s fundamental value, which may arise from two conventional sources: 1) characteristics of the business or industry, and 2) the company’s disclosure policy. The first source related to growth options and second source related to information asymmetry. From investors’ perspective the mechanisms and outcomes of every source are quite different. In this research we use from earning forecast dispersion as a proxy for measuring information uncertainty. We use stock turnover and price impact as proxies for information asymmetry. To control firm’s growth options, we use firm age, market-to-book ratio, and capital expenditure over total assets and Tobin’s Q. We use panel data regression model to analyze information. Our results indicate that information uncertainty has a positive relationship with information asymmetry and growth options.

Intrinsic value of a company depends on its financial and investment decisions. Companies with different investment opportunities are priced different in the market. The set of investment opportunities of companies are influenced by their current status in their life cycle.In this study, based on data from a sample of Tehran Stock Exchange listed companies during the period of 1385 to 1389, relationship between investment opportunities and earnings in according to corporate life cycle were examined.Results showed that there is a significant relationship between investment opportunities and earnings response coefficients. The results showed that the explanatory power of relationship between earnings and investment opportunities in companies differs with their life cycle stages. The companies that are in the growth phase of the life cycle, the relationship between earnings and investment opportunities is stronger than the companies that are in the recession phase of the life cycle.