Applying effective policies and regulations is necessary economical life of the capital market. Understanding the rights and obligations of individuals and institutions involved in the capital market is one of the essential requirements for the activity in this market. Responsibility for fulfilling obligations arising from stock exchange transactions is one of the most important issues in the field of the capital market, which was added to the ambiguity by adopting various regulations and instructions, so that the broker, clearing house (the central depository company) and the customer (genuine person) each one are known in different places Responsible for fulfilling obligations. In this research, we have tried with descriptive and analytical method by searching the authoritative sources and rules regarding all three responsible persons in terms of research constraints and describe the nature and responsibility of each of these institutions in settlement of exchange transactions. In short, in the transactions settlement structure, the clearing house, broker and genuine person, each are responsible for settling the deals; the main responsibility is with the customer. In the event of non-fulfillment of the customer's obligation, his/her broker is liable for performance of the obligations in the contracts in person on the basis of a warranty contract and in online contracts (made by the genuine person) under the ‘’contract of commitment to act third-party ’’, The clearing house operates as agent with the mechanism of binding payments netting.