Objective - The objective of this study is to investigate how institutional ownership and firm size affect firm value. The study also investigates the moderating effect of tax avoidance on the relationship between institutional ownership and the size of a firm on its value. Methodology/Technique - A model was developed and tested using a sample of 66 manufacturing companies listed on the Indonesian Stock Exchange between 2012 and 2014. Findings - The data was collected and analysed using a least square regression and moderated regression analysis. The analysis shows that institutional ownership and firm size affect firm value. The results also indicate that tax avoidance moderates the effect of institutional ownership and that of a firm's size on its value. Type of Paper - Empirical Keywords: Institutional Ownership, Firm Size, Tax Avoidance, Firm Value. JEL Classification: G30, G32, G39.

HardiFaculty of economic and business -Universitas Riau ABSTARCT The aims of this study was to obtain empirical evidence of how ownership structure ie institutional and managerial ownership affect firm performance. The study also examine the moderating role of tax avoidance on the effect of institutional and managerial ownerships on firm performance. A model was developed and tested using sample of 58 manufactured companies from 2012 to 2014, which is listed on Indonesian Stock Exchange. Data were collected and analyzed using least square regression and moderated regression analisys. The result showed that institutional ownership and managerial oenrrship affect firm performance. This study also showed that tax avoidance moderates the effect of both institutional and managerial ownership on firm performance.

The purpose of this study is to investigate factors that affect tax auditors’ performance, including the moderating role of work environment. The saturated sampling technique was employed as a sampling technique. Of the 166 tax auditors of the Directorate General of Taxes (DGT) in Riau Region as respondents, 132 questionnaires were returned, fulfilled the requirements, and were complete. Multiple regression analysis was used to test the first, second, and third hypotheses. However, moderated regression analysis was used for the fourth, fifth, and sixth hypotheses testing. The multiple regression analysis results showed that organizational commitment and job satisfaction have a positive effect on the tax auditors’ performance with a p-value for each 0.014 and 0.006. This indicates that the higher the organizational commitment and job satisfaction of the tax auditors, the better their performance. Meanwhile, job stress was found to have a negative effect on the tax auditors’ performance (p-value is 0.006); therefore, the higher the job stresses, the lower the performance. The results also found that work environment as a pure moderator strengthens the effect of organizational commitment on tax auditors’ performance (p-values of Z and X1Z each are 0.279 and 0.000). Meanwhile, work environment as a quasi-moderator also strengthens the effect of job satisfaction with p-values of Z 0.000 and X2Z 0.580. Work environment also moderates and strengthens the effect of job stress on the tax auditors’ performance with p-values of Z 0.000 and X3Z 0.597.