SEBI's Swift Ban on JPMorgan Unit Warns Traders Over New Closing System

India's market regulator SEBI has swiftly banned a JPMorgan affiliate and a domestic broker over alleged manipulation of the new Closing Auction System, just six days after the trades occurred on August 13. The interim order against Copthall Mauritius Investment Ltd. and Mansi Share and Stock Broking Ltd. alleges they placed and cancelled orders to influence the BSE Sensex's indicative closing price while benefiting from positions in Sensex options. The unusually fast action, described as "unprecedented" by a former SEBI board member, signals heightened scrutiny of the new mechanism. The CAS, introduced this month, concentrates trading activity into a defined auction window, making surveillance easier for regulators. The ban remains until the entities return nearly Rs 3.7 crore in alleged unlawful gains, and follows SEBI's earlier investigation into Jane Street Group, which took over a year to reach enforcement.