An individual who does not belongs to a trading associate of the stock exchange but he works as an agent for other trading members and help them to deal with the buying and selling of stocks is known as a sub-broker. Any agent claiming to be a sub-broker won't be considered as one unless he has registered his identity in SEBI and has received the certificate of registration. According to the terms and conditions implemented by SEBI, all the trading members (regardless of the number of shares they hold) must conduct a proper check on the sub-broker they're buying and selling shares through. Apart from that, it is a must to get into a written agreement with your sub-broker to avoid any future conflicts.