The recent famous financial frauds have demonstrated that in many cases the auditor was either responsible for or an accomplice in their manifestation. Thus, the auditor plays an important role in ensuring a true and fair view regarding the financial position and performance of the company. International standards on auditing indicate that the financial auditor's main objective is to serve the stakeholders' interests by expressing an independent, objective and competent opinion regarding the accuracy of information from financial statements. Also, according to audit standards, the auditor has the responsibility to assess fraud risk and how it could influence his opinion. The purpose of this study is to test if there is a connection between the affiliation of the client-company to an auditor who is member of Big4 and the incidence of financial fraud. The research results indicate the existence of a company profile that is defrauded or not defrauded. Starting from a series of factors associated to the financial auditor, a deterministic model was proposed in the study for estimating the probability of being defrauded. For the validation of the working hypotheses, a sample consisting of 200 defrauded and not defrauded companies was selected, quoted on New York Stock Exchange. Research results were obtained by processing the data with SPSS 19.0.