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The Securities and Exchange Board of India (Sebi) has proposed a revamp of the settlement methodology for derivatives contracts following concerns that the month-old closing auction session (CAS) system was leading to abrupt price swings and market uncertainty. In a consultation paper issued on Saturday, the market regulator suggested expiry-day settlement prices for index and stock derivatives could be calculated using trades from the last 30 minutes of the continuous trading session (CTS) and 10 minutes of the closing auction session (CAS), under a blended volume-weighted average price (VWAP) approach. As an alternative, the regulator has proposed retaining the existing VWAP methodology initially, with settlement based only on trades during the final 30 minutes of continuous trading, before potentially shifting to the blended approach after at least a year of experience with CAS. Mint was the first to report on 7 September that the stock market regulator may look to bring back the old mechanism to settle derivative contracts on expiry days, with a proposal to settle weekly and monthly derivatives using the previous VWAP model, or using a combination of VWAP and CAS prices. The proposals come barely weeks after CAS was introduced for F&O stocks on 3 August. Under the new framework, the closing price of securities is determined through an auction rather than the VWAP of trades in the final 30 minutes of continuous trading. Derivatives, however, continue to trade around the closing process, particularly on expiry days. Sebi’s review follows feedback from market participants about the interaction between cash and derivatives markets during CAS, price movements in certain index option contracts, and so on. The regulator noted that derivatives activity remains concentrated near the close, with trading during the 10-minute CAS period accounting for 4.13% of the day’s premium turnover on NSE and 6.79% on BSE in the period studied. Sebi has also proposed stopping the dissemination of the indicative index value (IIV) during CAS while continuing to provide indicative equilibrium prices (IEPs) for individual securities. The draft paper said that the IIV, derived from evolving IEPs, can be mistaken for an actual index level, even if no trades have taken place at that level. On market timings, the market regulator has suggested two alternatives. Under the first, CTS for CAS stocks would run until 3:30pm, followed by CAS from about 3:30pm to 3:40pm, with derivatives trading continuing until 3:45pm. Under the second, the existing 3:15pm cut-off for CTS in CAS stocks would remain, CAS would run until 3:25pm and derivatives trading would end at 3:30pm. The regulator has separately proposed reducing the transition period between CTS and CAS from five minutes to up to one minute, while cutting the post-CAS derivatives trading window from 10 minutes to five minutes. Another proposal seeks to curb the cancellation of limit orders placed beyond 1% from the reference price during CAS. Such orders could continue to be placed within the existing 3% plus or minus price band, but once they move beyond 1% plus or minus price band, they could not be cancelled. Traders would only be allowed to improve the price. Sebi has also proposed allowing unexecuted quantities from iceberg orders to move into CAS as normal limit orders, with the entire pending quantity disclosed in the auction order book. The aim is to ensure that genuine trading interest remaining at the end of continuous trading contributes to closing-price discovery. An iceberg order is a large trade split into smaller portions so that only a small part of the total order is visible to the public market at any given time. The market regulator has invited public comments on the seven proposals until 3 October. Apoorva is a Mumbai-based journalist at Mint who covers the Securities and Exchange Board of India (SEBI), tracking the pulse of India’s capital markets, regulatory developments and the people who operate within them. She holds a postgraduate diploma in business and financial journalism from the Asian College of Journalism, where she developed a strong foundation in markets, companies, and economic policy. She began her journalism journey with an internship at Bloomberg, where she worked across beats such as real estate, infrastructure, capital markets, and deals, which helped her understanding of business and finance.<br><br>She is guided by the belief that everything in this world can be explained in simple and fewer words, and that idea shapes how she approaches her writing. She aims to cut through complexity and present nuanced regulatory and financial developments in a way that is both accessible and meaningful to readers.<br><br>When she is not tracking market chatter, Apoorva can usually be found deep into a fiction novel or out on a long run. She is also a trained classical dancer in Bharatanatyam, Mohiniyattam, and Kathakali. Catch all the Business News , Market News , Breaking News Events and Latest News Updates on Live Mint. Download The Mint News App to get Daily Market Updates. Oops! Looks like you have exceeded the limit to bookmark the image. 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