Graded Surveillance Measure (GSM) is a system used by the Indian stock exchanges to monitor the trading activity of securities and identify any unusual or suspicious trading behavior. Under GSM, securities are placed under different levels of surveillance based on their trading activity. Securities with normal trading behavior are placed under lower levels of surveillance, while securities with abnormal or suspicious trading activity are placed under higher levels of surveillance. The GSM framework helps to monitor trading activity and take appropriate action if any unusual activity is detected. It is an important tool for maintaining market integrity and ensuring fair trading practices in the stock market.