The present study is a descriptive-analytical study that has been conducted with the aim of examining the characteristics of the legal system governing financial instruments in mutual funds in the stock exchange. Mutual funds as investable financial institutions buy and sell shares. Which is mentioned in the Securities Market Law. In this study, the researcher seeks to answer the question of what are the characteristics of the legal system governing financial instrument transactions?Initially, financial providers contribute financially by consolidating their financial resources and distributing capital, and referring to an investment fund can be considered as a kind of proxy according to which the investment fund in using funds and organizing the organization and management of advocacy affairs.Finds. The results showed that mutual funds are located and operate in the legal environment of the stock exchange. In the first place, partnership (legal) contracts were examined by referring to the text of the law and analyzing it from various sources. In this section, company contracts, Mudaraba, advocacy, peace and forgery were stated and then, based on the characteristics of each contract, an analysis of the legal system governing the financial instruments of investment funds was presented