Bourses and brokers may win from India’s proposed auction revamp

Stock exchanges and brokers may be among the biggest beneficiaries of the Securities and Exchange Board of India’s proposed changes to the newly launched closing auction system that’s caused chaos, while market makers may face tighter constraints.

That’s the takeaway from market players after the regulator suggested a sweeping revamp of the mechanism that’s spurred wild swings at the end of trading sessions. In a discussion paper released on Saturday, SEBI made several proposals, including to determine the settlement price based on a blend of the 30-minute volume-weighted average price and a 10-minute auction window — or retain the old VWAP methodology for a year before shifting to the blended system.

In either scenario, the eventual price would lean more heavily on the continuous trading session, where the bulk of market activity takes place. That shift could make the closing process more predictable and help restore confidence.


Meanwhile, market makers could face a less friendly regime as the regulator suggested restrictions to cancellation orders.

“The proposals are broadly positive for the market infrastructure ecosystem,” said Kruti Shah, a quantitative analyst at Equirus Securities. The changes should make the closing process more orderly and reduce some of the uncertainty that has emerged around price discovery and expiry-day trading, benefiting exchanges and intermediaries other than market makers, she said.

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The closing auction system introduced on Aug. 3 was meant to improve end-of-day prices and align India with other major global bourses. Instead, it led to unexpected wild moves at the end of the trading day, both in the equities and derivatives markets, as well asduring last month’s MSCI Inc. index rebalancing. The episodes fueled concerns over thin liquidity, the potential for investors to influence closing prices and the difficulty of managing large positions during the short auction window. Calls quickly grew louder for a review of the mechanism that affected well-established trading strategies.

For the exchanges, the impact was clear: In August, the daily notional turnover for futures and options on the National Stock Exchange of India Ltd., the nation’s leading bourse that’s scheduled to list later this month, hit an 18-month low. Meanwhile, shares of listed BSE Ltd. posted their worst monthly loss in a year as the daily notional turnover fell to the lowest since July 2025.

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Giving a greater weight to the 30-minute VWAP window would help keep the final price closer to that during the regular session, potentially restoring trust and encouraging trading. Listed brokers and capital-market companies including Motilal Oswal Financial Services Ltd., Angel One Ltd. and Billionbrains Garage Ventures Ltd. could benefit.

Market makers could be hurt by the potential changes because they would restrict their ability to cancel orders when prices move by more than 1% during the auction. That could leave them stuck with orders placed at outdated prices, increasing the risk of losses if the market shifts before the auction closes.

The move, aimed at making displayed orders more meaningful and limiting the ability of participants to rapidly pull liquidity, could make the firms more cautious about displaying liquidity in the first place, according to Ravi Varanasi, founding partner at SPVR Consultants and former business head at the NSE. A short no-cancellation period before matching may be a better solution, he added.

SEBI is seeking feedback on the suggestions by Oct. 3.