This study examines Firstly, the effect of tax avoidance practices on stock returns and Firm risks, and the moderating role of Ownership Concentration and Audit Firm Size, using sample of 330 observations of 55 non-Financial Listed Egyptian firms for the period 2013:2018. Secondly, re-test through additional analysis the effect of the ownership concentration and audit firm size as two control variables in addition to the firm size, leverage, working capital, and sales as other control variables. Finally, a sensitivity analysis was conducted to examine the effect of different tax avoidance measurement method on the main relationships. The results indicate that tax avoidance practices negatively affect stock Returns but positively affects Firm risks. And the results did not support the moderating role of ownership concentration and Audit Firm Size neither for tax avoidance and returns relationship nor tax avoidance and firm risks. The additional analysis reveals that both ownership concentration and Audit Firm Size are significant as control variables in both main relationships regression models, and It was found that the other control variables increased the explanatory Power of them. The sensitivity analysis results refers that changing the method of measuring tax avoidance affects the significance of the main relationships.

This research investigates the effect of the quality of the audit committee, and cash incentives, on the Intention of Whistle-Blowing the Financial Wrongdoings, in the context of gender and managerial level as moderators variables in the Egypt's business environment. This research basis on an experimental design, Using a sample of (416) observations, Participants were (104) accountants and internal auditors, and the experimental design was carried out through fundamental and additional analysis. The results of the fundamental analysis reveal that the quality of the audit committee and cash incentives positively affects the Whistle-Blowing Intention. And the joint effect of the quality of the audit committee and cash incentives on Whistle-Blowing Intention also supported. And I find evidence support the interaction effect of gender, that the quality of the audit committee and cash incentives increases the Whistle-Blowing Intention in males greater than females, while i did not find evidence on the interactive effect of the managerial level. The additional analysis results support the main effect of gender on Whistle-Blowing Intention, but did not find evidence on the main effect of managerial level or the joint effect of gender and managerial level on the Whistle-Blowing Intention in Egypt's business environment.