JPMorgan Sensex Manipulation Probe: What SEBI Action Means for Crypto Traders

India’s market regulator, the Securities and Exchange Board of India (SEBI), has officially barred JPMorgan Chase & Co.-owned entity Copthall Mauritius Investment and a domestic firm, Mansi Share and Stock Broking Pvt Ltd from accessing the securities market. The action follows alleged manipulation of the Sensex closing price during the Closing Auction Session (CAS) on August 13, an expiry day for Sensex derivatives. SEBI has also impounded ₹3.68 crore in alleged wrongful gains from the two entities.

SEBI Bars JPMorgan’s Copthall and Mansi Over Alleged Sensex Manipulation

On 19 August 2026, SEBI issued a 46-page ex-parte interim order restraining Copthall Mauritius Investment Ltd, a Mauritius-based foreign portfolio investor owned by JPMorgan and Mumbai-based Mansi Share and Stock Broking from trading. The order, passed by Whole-Time Member Kamlesh Chandra Varshney, stems from alleged manipulative trading during the CAS on the BSE Sensex on 13 August 2026, the weekly expiry day for Sensex derivatives contracts.

On the afternoon of the CAS window, SEBI’s surveillance systems flagged three sharp and short-lived spikes in the Sensex’s Indicative Equilibrium Price (IEP): a 362.02-point surge in around 2 seconds, a 132.67-point move in 12 seconds and a of 405.08-point rise in 28 seconds. The Sensex ultimately closed at 78,079.96 (or approximately 78,080). SEBI said the index would have closed near 77,840 based on comparable Nifty movement.

How Heavy Orders Allegedly Moved Sensex Closing Prices

According to the order, Copthall placed large, aggressive buy orders across Sensex constituent stocks at or near the maximum permissible limit of 3% above the reference price (approximately 77,829.60). In the first spike it accounted for 99.91% of the buy-order value, in the second 96.09% and in another relevant period 85.21%. The firm later cancelled a substantial portion of these orders (around ₹98 crore worth). SEBI said the activity appeared to be aimed at driving the IEP higher in line with Copthall’s long call and short put position on expiring Sensex options.

In parallel, Mansi Share and Stock Broking (proprietary account) took the opposite approach. It placed aggressive sell orders aggregating about 12.65 lakh shares (worth roughly ₹143–145 crore) across eight Sensex constituents at prices significantly below the reference level (near 2.5% or lower). These orders temporarily crushed the IEP for about four to five minutes, and then almost all were cancelled when the firm had squared off its put option positions at a profit.

What It Means for India’s Expiry-Day Traders and Market Integrity?

SEBI has stated that the two entities were not in sync with each other and that each entity independently adopted highly aggressive price impacting strategies in accordance with their derivatives positions. The regulator’s estimates of prima facie wrongful gains were ₹2.96 crore for Copthall and ₹71.65 lakh for Mansi, making a total of around ₹3.68 crore (or 384,000 to 386,000). These amounts have been ordered to be impounded and placed in fixed deposits with a lien in SEBI’s favour.

Meanwhile, both entities are prohibited from participating in the equity-segment CAS, including placing, modifying, or cancelling orders, given 21 days to respond as the SEBI probe continues. For Mansi, the restrictions apply specifically to its proprietary trading account. SEBI also directed freezes on bank and demat account debits (with limited exceptions), required asset inventories, and ordered the closure of open positions.

Furthermore, the rapid six-day enforcement signals heightened SEBI scrutiny of concentrated institutional activity around weekly expiries and the new CAS mechanism. Market participants may be more exposed to the risk of significant canceled orders affecting the settlement prices that determine options payoffs. Traders should be more vigilant in monitoring the order books and index spikes on future expiry days.

Related: CAS No-Trade Day: Why F&O Expiry Strategies May Need a Rethink

Related: Why Nifty and Sensex Closed in Different Directions Under India’s New Auction System