A stock broker, sub-broker and authorised person are important intermediaries in the securities market who facilitate transactions between investors and stock exchanges. Although their functions are related, they differ in terms of registration, authority, responsibilities and relationship with stock exchanges. A stock broker is a registered intermediary who is a member of a recognised stock exchange and is authorised to buy, sell or deal in securities on behalf of investors. A stock broker must obtain registration from the Securities and Exchange Board of India (SEBI) and comply with the rules, regulations and by-laws of the stock exchange. The broker provides trading facilities, maintains client accounts, executes orders, offers investment-related services and ensures compliance with regulatory requirements. The stock broker has a direct relationship with the stock exchange and bears primary responsibility for all transactions conducted through its platform. A sub-broker is an intermediary who acts on behalf of a stock broker and assists investors in dealing with securities markets. A sub-broker does not have direct membership of a stock exchange but works under the supervision and control of a registered stock broker. The sub-broker introduces clients, provides trading assistance, collects information from investors and helps in executing transactions through the broker’s system. The activities and conduct of the sub-broker are regulated, and the stock broker remains responsible for the actions of the sub-broker connected