تاثیر خوش‮ بینی مدیران بر هم زمانی قیمت سهام در شرکت‮های پذیرفته‮ شده در بورس اوراق بهادار تهران

هم‌زمانی قیمت معیاری نسبی از اطلاعات خاص شرکت در مقایسه با اطلاعات بازار و صنعت است که در قیمت سهام منعکس می‌شود؛ لذا با شفافیت رابطه معکوس دارد. خوشبینی یکی از انواع سوگیری‌های رفتاری مدیران است که آنها را از ارزیابی درست شرکت باز می‌دارد. شفافیت اطلاعات تحت تاثیر این ویژگی رفتاری است. خوش‌بینی منجر به کاهش کیفیت و محتوای اطلاعاتی افشاها می‌شود که به تبع آن هم‌زمانی قیمت افزایش می‌یابد. پژوهش حاضر به بررسی تاثیر خوش‌بینی مدیریت بر هم‌زمانی قیمت با استفاده از داده‌های 112 شرکت طی سال‌های 1389 تا 1395 پرداخته است. برای سنجش هم‌زمانی از مدل بیوتروسکی و روستون (2005) و برای خوش‌بینی از سه شاخص باقی‌مانده مدل رشد، دقت پیش‌بینی سود فصلی و مازاد مخارج سرمایه‌ای استفاده شد. یافته‌ها نشان داد مطابق با مباحث تئوریک، خوش‌بینی (مازاد مخارج سرمایه‌ای) اثر مثبت و معناداری بر هم‌زمانی دارد. درخصوص دو پروکسی دیگر خوش‌بینی، اثر معناداری مشاهده نشد.

The impact of Manager Optimism on prices Synchronization in TSE

Introduction Optimism is behavioral bias that prevents managers from properly evaluating their company. The literature shows that the information transparency is affected by this managerial behavioral characteristic and the stock price synchronicity will increase. Stock price synchronicity is a relative measure of company specific information in comparison with market and industry data that is reflected in stock prices; therefore, it is inverse to transparency. This study aimed to investigate the effect of managerial optimism on stock price synchronicity. For this purpose, managerial optimism has been measured based on three criteria including: accuracy of profit prediction by managers, surplus of capital expenditures and the remainder of the company’s growth model. Piotroski & Roulstone’s model (2005) has been used to measure the stock price synchronicity.   Research Hypothesis This study is aimed at examining the effect of managerial optimism on stock price synchronicity. Based on the developments of the literature, one hypothesis is developed. The hypothesis is stated: The managerial optimism have positive impact on stock price synchronicity.   Methods This research is categorized as empirical and descriptivecorrelation study. To obtain research results via referred variables in last section, a multivariate regression and panel model has been used. The data required for the research were gathered from 112 companies listed on Tehran Stock Exchange during a 7year period from 2011 to 2017. The STATA 14.1 package are utilized to run the analysis.   Results The results of testing the research hypothesis suggest that managerial optimism influences positively and significantly on stock price synchronicity based on surplus of capital expenditures indicator for measuring it. No significant effect was observed on the other two proxies (accuracy of profit prediction by managers and the remainder of the company’s growth model).   Discussion and Conclusion Recent studies in accounting investigate the impact of managerial optimism on corporate investment, financing, and dividend policies, as well as managerial forecasts and financial misreporting. This research contributes to this literature by providing evidence on the effects of managerial optimism on stock price synchronicity. The findings show that managerial optimism hasba significant positive impact on stock price synchronicity. In other words, managerial optimism decreases information quality and transparency. As optimistic managers overestimate future returns from their firms’ projects; overvalue their firms’ projects and equity; and invest in negative NPV projects mistakenly perceiving them to be positive NPV investments, it is predictable that optimism and price synchronicity will be positively related.