- India's new Closing Auction Session (CAS) has sparked a second jump in the Nifty index on expiry, following its introduction by Indian stock exchanges.
- Foreign investors have backed the CAS, while domestic institutions have opposed it, leading to a divided response as SEBI continues to press ahead with the reform.
- The strongest push for CAS came from global passive investors, who wanted alignment with international market practice and execution at benchmark-index prices to reduce tracking error.
- Domestic institutions, brokers, exchanges, and traders opposed CAS, arguing that India lacked the institutional depth and two-sided liquidity needed for reliable auction-based price discovery.
- CAS went through two rounds of public consultation and six to seven meetings with market participants; one participant said there was never a consensus on whether India was ready.
- Opponents argued the existing Volume Weighted Average Price (VWAP) framework was already efficient; dealers used the 3:00 pm to 3:30 pm window to execute large institutional orders.
- The main liquidity worry was that a thinly populated auction could produce economically unreliable closing prices; SEBI responded with data showing nearly 90 percent of institutional activity on index rebalancing days already occurred in the final 30 minutes.
- To address derivatives concerns, SEBI directed exchanges to publish a continuously updating indicative equilibrium price during the auction as a reference for derivatives traders.
- After implementation, Uttam Bagri said institutions were failing SEBI by not participating; on the first day, heavyweight Nifty constituents settled well above their 3:15 pm prices, creating an unusual divergence with the Sensex and futures, with some calling it a first-day phenomenon.
- Monday's debut of the closing auction produced an official close about 0.8% above the pre-auction level, sparking confusion across dealing rooms as futures remained largely stable.
India's new Closing Auction Session (CAS) has ignited a significant debate among market participants, as the Nifty index experienced a notable jump during its second expiry under the new system.12
The Securities and Exchange Board of India (SEBI) implemented the CAS to align Indian markets with international practices, responding to demands from global passive investors. However, domestic institutions raised concerns about the market's readiness for such a reform, citing a lack of institutional depth and liquidity necessary for reliable price discovery.3451112131415
The first day of the CAS saw a sharp divergence in closing prices, with the Nifty index closing approximately 0.8% higher than pre-auction levels, which sparked confusion among traders as futures remained stable.
Critics of the CAS argue that the existing Volume Weighted Average Price (VWAP) framework was functioning efficiently, and that an under-populated auction could lead to significant price distortions.910
SEBI, however, defended the reform by presenting data indicating that nearly 90% of institutional activity on index rebalancing days already occurs in the final 30 minutes of trading.
As the market adjusts to the new system, concerns persist about the potential for liquidity issues, especially on days of high institutional flow.
“It is the institutions which are failing SEBI,” said a participant, emphasizing the need for greater participation to ensure the success of the CAS.
The ongoing adjustments and reactions from market participants will be crucial in determining the long-term viability of the CAS in India's evolving financial landscape.
“Monday's debut produced an official Nifty close about 0.8% above the pre-auction level, confusing dealing rooms while futures stayed stable; on the expiry session the auction pared losses to lift the close about 0.6% from 3:15 p.m. Uttam Bagri said institutions are failing SEBI by not participating in the session.”
