Private companies demand a differentiated analysis towards private enterprises in order to determine the fair price of its shares. This happens because of the diversification and transparency difficulties related to the private companies transactions, where only a few deals are executed or known and there are not many buyers and sellers. Moreover, the final price of a non-listed asset is arbitrary and the information asymmetries raise obstacle to the fair value calculations. Even though many studies in several countries confirm the existence of a discount between the value of a private company versus its stock market listed peers, there are no researches focusing in the Brazilian market. In this regard, this thesis uses the local market merger and acquisitions information occurred in the period between January of 2000 and July of 2013, with the purpose to estimate the discount between private and public companies.