SEBI bars JPM unit, Mansi over Sensex CAS auction

What SEBI’s interim order alleges

SEBI has passed an ex-parte interim order against Copthall Mauritius Investment Ltd and Mansi Share and Stock Broking Pvt Ltd. The regulator’s order relates to suspected manipulation of the Sensex closing price during the Closing Auction Session (CAS) on BSE. The trades under scrutiny were executed on August 13, 2026, which was a Sensex weekly expiry day. SEBI said it found prima facie evidence of manipulative trading during the CAS window. The order states that immediate directions were necessary to protect market integrity and fair price discovery. SEBI also noted that letting the entities continue in CAS pending examination could risk recurrence of the conduct. The directions are interim in nature and will remain in force until further orders. SEBI said its examination of the matter will continue.

Entities named: Copthall Mauritius and Mansi Share

Copthall Mauritius Investment Ltd is described in reports as a Mauritius-based unit of JPMorgan Chase and Co. The other entity named is Mansi Share and Stock Broking Pvt Ltd. In Mansi’s case, SEBI’s restrictions apply to its proprietary trading account, as per the order. SEBI’s action restrains both entities from accessing the securities markets, subject to qualifications specified in the order. The interim directions also specifically target participation in the equity-segment CAS. Both entities have been prohibited from participating, directly or indirectly, in the CAS until further orders. SEBI’s order requires disclosures from the noticees about their holdings and accounts. The action has been widely discussed online because it involves the new closing auction mechanism and an expiry-day window.

The session in focus: BSE’s Closing Auction Session

The alleged conduct relates to BSE’s Closing Auction Session, the auction-based system used to determine closing prices. SEBI’s order focuses on activity that could influence the indicative equilibrium price during this window. According to reports referencing the order, the entities placed large orders in Sensex stocks during the closing auction. The order states that, in some securities, these orders accounted for more than 90% of all orders in the session. SEBI’s concern, based on the interim order, is that such order concentration can affect the closing price formation process. The regulator connected this suspected influence to potential benefits in derivatives positions held on the same day. The scrutiny is tied to August 13, when derivatives contracts linked to the Sensex had a weekly expiry. The order also recorded that the Sensex closed at 78,080 on that day.

SEBI’s view on motive: benefit in options positions

SEBI said, in the interim order, that each noticee tried to create a favourable move for themselves in Sensex constituents. The stated purpose, as recorded in the order, was to enrich themselves with wrongful gains in their expiry-day Sensex option positions. SEBI also observed that Copthall’s trading activity prima facie generated an asymmetric wrongful gain in the derivatives segment. The order links the alleged equity CAS trades with a derivatives payoff on an expiry day. This is a key reason the regulator’s directions extend beyond just one cash-market session. The interim order characterises the conduct as manipulative, while emphasising that the findings are prima facie. The case has drawn attention because CAS is intended to support fair price discovery at the close. SEBI’s order signals that trading patterns around the closing auction are under active surveillance.

Wrongful gains estimated and amounts impounded

SEBI has prima facie estimated wrongful gains of ₹2.96 crore for Copthall Mauritius Investment and ₹71.65 lakh for Mansi Share and Stock Broking. Together, SEBI has put the total at ₹3.68 crore and impounded that amount corresponding to the alleged wrongful gains. SEBI has directed that the bank accounts of the two entities be impounded to the extent of their respective amounts. The regulator has also directed the impounded amounts to be placed in fixed deposits under lien in favour of SEBI. This structure is meant to ring-fence the money while the examination continues. The interim directions are framed as protective steps rather than a final determination of liability. Multiple reports also describe the order as running to 46 pages. The table below summarises the amounts and key interim actions mentioned in the order.

Market access bar and wider account controls

Beyond impounding, SEBI restrained both entities from accessing the securities markets, subject to qualifications set out in the order. The regulator also prohibited them from placing, modifying or cancelling orders in the CAS until further orders, as described in reports. SEBI restricted relevant bank-account and demat-account debits for the noticees. The interim directions also barred transfer or redemption of securities and mutual fund units held by the noticees. SEBI further prohibited them from disposing of or alienating assets without SEBI’s permission. These directions are designed to preserve assets and reduce the risk of further market impact during the ongoing examination. The order calls for the noticees to provide an inventory of assets, bank accounts, demat accounts, securities and investments. Reports also mention a timeline of 15 days for submitting a complete inventory.

Timelines for replies and the chance of a hearing

SEBI’s interim order gives the noticees an opportunity to respond. The noticees have 21 days from receipt of the order to file their replies or objections. The order also states that they may seek a personal hearing. This is consistent with the order being ex-parte and interim, meaning it was issued without hearing the parties first. SEBI’s directions are therefore not the final word on the matter, based on the language in the reports. At the same time, the restrictions take effect immediately and remain in force until further orders. SEBI has indicated it will continue examining the trades and related positions. The case is being watched because it tests how enforcement will work around the closing auction mechanism. Online discussions have focused on how regulators balance quick action with due process in fast-moving markets.

Why closing auction integrity has become a talking point

The closing price is a widely referenced number in the market and is central to settlement and valuation. SEBI’s order frames the CAS as important for fair price discovery at the close. The regulator’s concern, as stated, is that conduct observed on August 13 could expose the market to recurrence risk if not immediately restrained. This is also why the order includes a specific prohibition on CAS participation, not just a general market bar. The focus on an expiry day matters because index-linked derivatives positions can be sensitive to closing levels. The interim order links the alleged behaviour to a benefit in Sensex option positions on the same day. Reports also highlight that large orders in the closing auction made up a significant share of all orders in some securities. SEBI’s intervention signals that closing-auction activity is being monitored for patterns that could distort the equilibrium price.

What market participants are watching next

Market participants are now tracking two things: the continuation of SEBI’s examination and whether the interim restrictions are modified later. The immediate facts, as per the order, are an alleged CAS manipulation on August 13 and the impounding of ₹3.68 crore. Another focus is the operational impact of restrictions on bank and demat debits, and limitations on asset transfers. Observers are also noting that SEBI has barred participation in the equity CAS, including restrictions tied to Mansi’s proprietary account. The order’s fixed-deposit lien requirement is also being discussed as a way to secure alleged gains while the process continues. The timeline for replies, set at 21 days from receipt, provides the next formal milestone. Any personal hearing requested by the noticees could also shape the sequence of events. Until further orders, SEBI’s interim directions keep both entities out of the CAS and restrained from the securities markets under the terms described.