MSCI Rejig Drives $4.2 Billion CAS Turnover as Stock-Level Volatility Surges

A sharp spike in activity marked the National Stock Exchange's Closing Auction Session (CAS) on September 1 as investors executed trades linked to MSCI's latest India index rebalancing. The auction window recorded turnover of $4.2 billion, making it one of the busiest sessions since the mechanism was introduced. 

The surge was driven by passive funds and institutional investors adjusting portfolios to reflect MSCI's latest inclusions, exclusions and weight changes. According to NSE data, the auction window accounted for 22 percent of the day’s cash-market turnover, and over 98000 investors participated in the auction session. In addition, the exchange noted that turnover during the CAS was about 42 times higher than the same period on the previous trading day.  

While the auction window handled a significant amount of rebalancing-linked trading, price action varied sharply across stocks affected by the review. 

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Out of 19 stocks that were expected to be added, removed or re-weighted in the MSCI exercise, 17 were eligible to participate in the auction session. Of these, nine traded at upper or lower 3% price bands in the closing auction, indicating the strength of stock specific moves in the final minutes of trade. 

Stocks added to the index saw mixed performance. Laurus Labs and Lenskart Solutions recorded CAS-linked price movements of 3%, even though both ended the day lower overall. Adani Energy Solutions, another inclusion, saw a 3% decline during the auction window after falling 10.4% through the session. Billionbrains Garage Ventures was also among the additions under the review.  

On the exclusion side, SBI Cards and Payment Services and Astral each witnessed a 3% decline during the auction session. Balkrishna Industries was also among the stocks removed from the index basket. 

The weight-adjustment category produced a varied outcome. Eternal, Indian Hotels and Colgate-Palmolive India registered auction-linked gains of 3%, while Adani Enterprises, Adani Ports, Adani Power and GMR Airports recorded declines during the closing session. Reliance Industries, which saw a reduction in index weight, logged a 1.4% CAS-linked decline. 

The impact was not limited to stocks directly affected by the review. Across the 210 counters eligible to trade in the auction session, 60 touched their permitted price bands. Of these, 47 stocks hit the upper band of 3%, illustrating the extent of concentrated order activity in a short trading window.  

Rajesh Palviya, Head of Research at Axis Securities, said such moves can occur when investors executing mandatory index-related trades have little flexibility on timing. According to him, participants needing execution often place orders at increasingly aggressive prices to improve the chances of getting trades completed. However, he also pointed to the sharp swings seen in several counters during the closing minutes as an area that requires continued monitoring.  

Beyond the price action, the rebalancing exercise offered insight into how effectively the auction mechanism absorbed expected index-related flows. 

The report noted that cumulative net inflows associated with the MSCI rebalancing were expected to be around $1.4 billion. Against that backdrop, the $4.2 billion turnover recorded in CAS represented around 30 times the average daily turnover seen since the launch of the system. 

However, the degree of absorption differed widely from one stock to another. 

Adani Power recorded auction volumes equivalent to 160% of the estimated rebalancing requirement, the highest among the affected stocks. GMR Airports achieved 134%, while Adani Ports recorded 132%. Adani Energy Solutions reached 122%, Adani Enterprises stood at 120%, and Swiggy registered 113% of expected rebalancing volumes. 

Strong participation was also seen in Eternal and Astral, both of which recorded 99% of estimated flows. SBI Cards and Payment Services reached 89%, Laurus Labs recorded 75%, while Lenskart Solutions and Balkrishna Industries each achieved 73% of expected rebalancing volumes through the auction window. 

Not all counters experienced the same level of execution. Colgate-Palmolive India saw only 33% of the estimated rebalancing volume completed through CAS. Indian Hotels recorded 49%, JSW Energy stood at 48%, Jio Financial Services achieved 54%, while Reliance Industries recorded 70% of projected flows.  

The data showed that although the closing auction window absorbed a substantial portion of index-driven trading activity, liquidity conditions varied significantly across stocks. In several cases, auction volumes exceeded estimated requirements, while in others the execution fell well below projected levels.