The study of effective factors seems essential since, the operation of profiting entities is very important in the decision of internal and external organization users. The effect of various factors on the assessment scale of operation was measured in different researches, e.g. the structure of ownership. In this study, the relationship between three kinds of various structures of ownership including the structure of shareholder's ownership and other firms and the structure of state ownership Q Tobin's operation scale of listed firms in TSE was considered. The effect of firm's age and size has considered as two control variables on the Q Tobin's operation scale. In this study, the statistical population is listed firms in Tehran Stock Exchange (TSE).

Theories are tested by multilateral Regression on the basis of T and F statistics. Finding shows that Q Tobin operation scale has significant relationship with two kinds of investment organization's ownership scale and other companies and state ownership, but it does not have significant relationship with minor shareholder's scale. Age and size of firms do not effect on Q Tobin operation scale as two control variables.