Internal audit system and profitability of business firm: A research on the companies in BİST 100

In our country, the bigger firms established internal audit system at the beginning of 1990s and adopted the organization system.The first begining point is financial audit and compliance audit. Due to these systems established in the advanced countries many years ago, small firms have grown safer and more profitable. In this study ,it is not only analysed why firms need to use internal audit , how the system can be built but also it proposes some advice according to the effects on financial determination. In addition, in order to prepare the risk anlaysis maps for the economical fundemantals, Small and Medium Sized Enterprises and family firms, the benefit of internal audit is emphasized and it is examined how to build the basis organization structure for the future big firms. Keywords: Internal Audit, Profitability, Risk Analysis, Management System, Audit, Financial Management