India’s Closing Auction System Faces $4 Billion Test During MSCI Index Rebalance

India’s contentious new closing auction system is preparing for its largest operational test as billions of dollars in passive-fund trades flow through the mechanism. The quarterly rebalancing of MSCI Inc. indexes on Monday will determine whether the platform can absorb large institutional orders without causing sharp price swings that have concerned traders since its introduction earlier this month.

According to Brian Freitas, founder of Auckland-based Periscope Analytics, the index changes are expected to spur approximately $5 billion in trading turnover by global passive funds, with about $4 billion passing through the Closing Auction Session (CAS). This volume is significant compared to the auction's typical daily turnover of roughly $125 million, with Freitas noting that expected flows are nearly 30 times normal handling capacity.

The upcoming rebalance places the Securities and Exchange Board of India's (SEBI) market reform under scrutiny following trader backlash. Last week, the BSE Sensex gauge experienced a flash crash during the 20-minute auction window, highlighting concerns regarding thin liquidity and market manipulation. Despite these issues and calls for modifications, SEBI Chairman Tuhin Kanta Pandey affirmed that the mechanism will remain in place to align the domestic market with global standards and reduce tracking error for passive funds.

MSCI stated that it will monitor the practical effectiveness of the closing auction based on feedback from market participants, clients, and index users. The latest quarterly review outlines several index adjustments. Lenskart Solutions Ltd, Laurus Labs Ltd, Adani Energy Solutions Ltd, and Billionbrains Garage Ventures Ltd are set to be added to standard indexes, while Balkrishna Industries Ltd, SBI Cards & Payment Services Ltd, and Astral Ltd will be removed. Additionally, a weight reduction in Reliance Industries Ltd is anticipated to trigger about $500 million in outflows, according to Abhilash Pagaria of Nuvama Wealth Management Ltd.

Pratik Oswal, chief of passive business at Motilal Oswal Mutual Fund, explained that most passive funds prefer executing trades through the auction window to stay close to the official closing price. However, the scale of the rebalance may require alternative execution strategies. Oswal noted that liquidity remains the primary execution risk, particularly in less-traded stocks where absorbing large orders without price impact is difficult. For less liquid names, funds may need to execute portions of their trades during regular market hours, while index heavyweights with deeper order books like Reliance are expected to absorb trades more smoothly.

Market observers note that attracting sufficient investor participation to build liquidity is a common hurdle for new auction systems. Andrew Sullivan, founder of Hong Kong-based Asian Market Sense, described the situation as a chicken-and-egg problem, stating that institutions must first observe that the system works fairly and free from manipulation before committing capital and deepening liquidity.

"The upcoming MSCI index rebalance serves as a crucial stress test for India's newly implemented closing auction system. When managing billions in passive flows through concentrated windows, market liquidity and execution risk become paramount for institutional investors. While regulatory reforms are essential to align domestic markets with global standards, regulators and exchanges must closely monitor market stability and address liquidity gaps in smaller stocks to build long-term confidence among market participants." — Dr. Shishir Gupta, Founder & CEO, StartupLanes