Measuring Corporate Tax Rates Effects on the Risk Level of Viet Nam Industrial Material Firms under a One Factor Model

The Viet Nam stock market has been affected by the financial crisis 2007-2009 and macro policies have been conducted. This study analyzes the impacts of tax policy on market risk for the listed firms in the industrial material industry as it becomes necessary. First, by using quantitative and analytical methods to estimate asset and equity beta of total 99 listed companies in Viet Nam industrial material industry with a proper traditional model, we found out that the beta values, in general, for many companies are acceptable. Second, under 3 different scenarios of changing tax rates (20%, 25% and 28%), we recognized that there is not large disperse in equity beta values, estimated at 0,741, 0,747 and 0,750.These values are lower than those of the listed VN construction firms. Third, by changing tax rates in 3 scenarios (25%, 20% and 28%), we recognized equity /asset beta mean and corporate tax rates have positive relationship. Finally, this paper provides some outcomes that could provide companies and government more evidence in establishing their policies in governance