Akbar Kanani - Department of Accounting, Marand Branch, Islamic Azad University, Marand, Iran
Seyyed Jaber Mirniya - Department of Accounting, Soofiyan Branch, Islamic Azad University, Soofiyan, Iran

The size of a company shows different perspectives of it in several studies. The present research is going to study the effect of the sizes of firms accepted in Tehran Stock Exchange on their operating performances. Our statistical sample includes ۶۶ firms during the time period between ۲۰۰۶ and ۲۰۱۰. The statistical method used in this research includes the independent t test and a bidirectional variance analysis method. The findings of the research show that the size of the firms affects criteria such as ROA, ROE, REVA, MVA, P/E, M/B, and Q statistically and it does not affect criteria such as EPS, ROI, RI, and EVA. Also regarding EPS and EVA, we can say that firms with big sizes affect these criteria the most and small firms have the least effects on ROI and RI criteria. Also in studying the simultaneous effects of the type of the industry and the sizes of firms on operating performances of them each of operating performance approaches (accounting, financial, value added and integrative approaches) is affected by the industry agent.

Firm Size, Operating Performance Based On Accounting, Financial, Value Added, And Integrative Approaches