SEBI CAS enforcement puts India’s new closing auction under spotlight
SEBI issued an interim order against two firms over alleged August 13 closing-auction manipulation and ordered ₹3.68 crore of estimated gains impounded pending investigation.
What changed
SEBI issued an interim order over alleged CAS manipulation; Reuters also reported a broker-confirmed operational change planned for September.
Why it matters
Closing-auction integrity affects benchmark prices, derivatives settlement and market confidence.
Who is affected
Equity and derivatives traders, brokers, index investors, fund managers and compliance teams.
Action required
Preserve “alleged” and “interim” wording; verify any September mechanics against exchange/SEBI circulars before implementation.
## What changed
SEBI has issued an interim order against Copthall Mauritius Investment and Mansi Share and Stock Broking over alleged manipulation during the new Closing Auction Session (CAS) on August 13. The regulator ordered a total ₹36.8 million, or ₹3.68 crore, to be impounded while the investigation continues.
SEBI estimated alleged wrongful gains of about ₹2.96 crore for Copthall and ₹0.72 crore for Mansi. The order concerns trading around Sensex-derivative expiry. CAS was introduced on August 3 and uses a 20-minute auction starting at 3:15 p.m. to determine closing prices.
Separately, three brokers told Reuters that SEBI has asked brokers to accept orders during the current 3:15-3:20 p.m. transition window from September to improve liquidity and price discovery. SEBI had not publicly commented on that operational change at the time of the report.
## Why it matters
Closing prices feed index values, derivatives settlement, NAV calculations and benchmarks. A thin closing auction can therefore have effects beyond one stock.
## Finin2min takeaway
Use careful legal language: the findings are alleged and the order is interim. Operational changes reported by brokers should also not be presented as a formal SEBI circular until official text is available.
**Watch next:** final orders, exchange circulars and September CAS liquidity.
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