This book deals with the search for the identification of the existence of abnormal variations in the price of shares of entities accused of involvement in accounting fraud or present normal indebtedness and financial leverage indexes. It was an analysis that used the conceptual bases of the study of events proposed by Campbel, Lo and Mackinlay (1997) and also of Modigliani and Miller's Propositions I and II (1963) in which, the average, minimum, maximum and standard deviation were calculated, associated with the use of the multiple linear regression method about the stock variation, among capital market entities, listed on the BM&FBOVESPA. Thus it was possible to identify the dispersion, the varied quantity and the relation of fraud, the degree of indebtedness and the degree of financial leverage with the oscillations in stock prices.