There are many factors affecting disclosure of accounting information and have impacts on risk level of business, such as: the following factors influenced on the disclosure level: tax rate, financial leverage, acquiring company size, recognized percentage of overprice for expected future profitability in relation to the transaction value. This research paper also analyzes the impacts of tax policy on market risk for the listed firms in the medicine industry as it becomes vital. First of all, we found that the beta values for many companies in general are appropriate by using quantitative and analytical methods for the estimation of asset and equity beta of 9 listed Vietnamese medicine companies with a better traditional model.Next, we have noted that under three different scenarios of adjustments in tax rates (25%, 25% and 28%), the equity beta values will not spread significantly, even if the is down to 20% and the risk dispersion will increase 0,512 to 0,513.Third, this analysis found that the risk-dispersion level in this sample analysis could be held to a minimum, if the tax rate is raised to 28% or to 25% , we found beta values and tax rate has positive correlation. Not only the paper propose some policy suggestion, bit it also recommends risk management plans including IT governance and security and risk to reduce operational risk. Specifically, it also proposes suggestions for enhancing disclosure policy of accounting information and risk policies of businesses.