India's securities regulator moved in just six days to ban a JPMorgan entity and a local brokerage over alleged manipulation of a brand-new closing auction mechanism
India’s market regulator just demonstrated what happens when you try to game a system that’s barely two weeks old. The Securities and Exchange Board of India (SEBI) issued an interim order banning Copthall Mauritius Investment Ltd., a JPMorgan Chase entity, and local brokerage Mansi Share and Stock Broking Ltd. from participating in Indian securities markets after alleged manipulative trading during the country’s newly introduced Closing Auction Session.
The most striking detail isn’t the allegation itself. It’s the timeline. SEBI moved just six days after the suspected manipulation occurred on August 13, 2026, a pace that would have been virtually unrecognizable from the regulator’s historical rhythm.
What happened during the closing auction
The Closing Auction Session, or CAS, launched on August 3, 2026, replacing the previous volume-weighted average price method. Instead of averaging prices over a period, the CAS runs a focused 20-minute auction window designed to land on one equilibrium closing price for eligible stocks. The mechanism mirrors what major exchanges like the NYSE and LSE already use.
On August 13, which happened to be the weekly expiry day for BSE Sensex derivatives, SEBI alleges that Copthall executed large buy orders totaling millions of shares during the CAS. Those volumes significantly exceeded industry norms for the session. Meanwhile, Mansi Share placed concurrent sell orders during the same auction window, many of which were later canceled.
The combined wrongful gains from this coordinated activity were estimated at approximately 36.8 million rupees, roughly $384,000. Of that total, Copthall’s share was around 29.6 million rupees, with Mansi’s portion at about 7.2 million rupees.
SEBI’s new enforcement posture
SEBI’s order, issued on August 19-20, came less than a week after the alleged activity. That kind of turnaround suggests the regulator was actively monitoring the new CAS from launch, essentially standing guard next to a mechanism it knew would attract testing from sophisticated market participants.
Both firms have been given 21 days from the order to respond and can potentially request a hearing to contest the allegations. To lift the ban, they would need to repay the impounded amounts.
