An Investigation about the Existence of Conservatism in Tehran Stock Exchange

Uncertainty and ambiguity in all aspects of today's life is unavoidable. In Heisenberg's Uncertainty Theory, uncertainty exists in the nature of events (Hammer, 1990). Accounting and financial reporting are not exceptions to this rule. Controls, probability of receiving payable accounts, profitability of assets, and in future cash flow are examples of this unavoidable ambiguity. Conservatism principle is the first and the most important way to face accounting transaction and events uncertainty. This principle come from Business Caveats Emptor that say payer must be careful to consistency in quality and quantity that is achieved with what he pays money for. Conservatism is one of the historical accounting principles and in the opinion of some theoreticians, conservatism is only a very primary and simple solution for facing future accounting ambiguity. This article investigates existence of conservatism in Tehran Stock Exchange. Research Hypothesis: To achieve the purpose of this study four research hypotheses were created. These research hypotheses are listed below: There is income asymmetry existence in companies accepted in Tehran Stock Exchange. There is a difference in Non Operational Accrual on duration. There is a significant different between Skewness of operational cash flow and Skewness of cash division. Difference between market value and book value can be divided to fixed and variable sections. This study is a semi-empirical research and uses parametric and nonparametric tests for investigation. The study began with review theories and related literature of accounting conservation principle, then variations were calculated and lastly statistical tests were run and results were achieved. The variations used in this article are: Stock return. Kind of profitability, which is dummy variation profitability. Book value of equity at the end of fiscal year. Market value of equity at the end of fiscal year. Profit before extra ordinary items to market value of equity. Non Operational Accrual Operational cash flow. Using current models in related literature, the present article investigates the existence of conservation. For testing hypothesis we use below models: Basu's (1997) model that is explained in the following equitation: Givoly and Hayn's (2000) model explained in the following equitation: Bevear and Rayn's (2000, 2005) model that tries to recognize conditional conservation and unconditional conservation and with comparing lag in accounting in duration of time. The research data was infact prepared by studying 194 corporations which have been active in Tehran Stock Exchange during 1999-2008. For the purpose of testing hypothesis, we used simple multi-regression analysis in enter mode, independent samples T Test, one-way ANOVA analysis, Kolmogorov–Smirnov test, Kruskal-Wallis test and skewness of distributions for statistical analysis. The results show that the difference in the timeliness of bad versus good news does not exist for the most parts (in levels of all corporate and different industries). In addition, meaningful difference in non-operational accruals in the course of time depends on statistical test. We observed a difference in skewness of distributions for operational cash flow and distributions divided in cash. In all corporations level skewness of distributions for operational cash flow is high but in different industries level Skewness of distributions for divided in cash is higher. Lastly testing on differences between market value and book value of net assets indicates that both kinds of conservation (conditional and unconditional) exist in both levels and they are ascending in periods of research. Discussion & Results of research shows different conclusions so to accept or to reject the existence of conservatism in Tehran Stock Exchange is not so simple and clear. The reason is because of the use of different models assumptions and conditions each of which can be considered in different positions.In fact, Basu's model tries to study stock return and asymmetric timeliness for speed in action of market when it achieves good news (profit) versus bad news (loss), but Givoly and Hayn's model studies the amount of non-operational accruals that management used in accounting and financial reporting, and lastly Bevear and Rayn's model tries to study conditional conservatism and unconditional conservatism; in addition they are different in their use of skewness of distributions for operational cash flow, and Skewness of distributions for divided in cash.