ANISHA AND DEV KUMAWAT, THIRD AND FOURTH- YEAR STUDENTS AT TNNLU, TIRUCHIRAPPALLI
INTRODUCTION
The Securities and Exchange Board of India (‘SEBI’) has released a consultation paper on 22 August, 2025, suggesting the commencement of Closing Auction Session (‘CAS’) in the equity share market or stock market. The new framework is not just a reform to the market structure for ameliorating the closing- price integrity rather it has far-reaching implications for Indian securities law and corporate governance. The proposed amendment related to CAS is far more than the statistical closing price for the trading day, as it has paramount implications for the legal and contractual matters, none the less from takeover regulations, delisting thresholds to mutual fund net asset valuations and the determination of settlement obligations. Through this, SEBI is not just affecting the economic framework of the market but also proposing a new regulatory and commercial frameworks by recalibrating on determination of prices.
To address this issue, this article examines the legal and market issues that are raised by CAS ranging from takeover thresholds, delisting processes mutual fund valuations to its impact on insider trading enforcement and minority shareholder protection. Thus, a comparative analysis has been drawn focusing on its regulatory safeguards and highlighting the opportunities and risks of the proposed framework. Ultimately, it suggests a layered regulatory approach to harmonize SEBI’s twin objectives of accurate price discovery and investor protection through greater transparency, real-time surveillance and protective mechanisms.
FROM VWAP TO CAS: A STRUCTURAL SHIFT IN PRICE DISCOVERY
The proposed amendment sharply contrasts with the present method of calculating the price of the stocks for each company i.e. the closing price. Currently, the closing price is calculated from the Volume-Weighted Average Price (‘VWAP’), i.e. the weighted average price of trades that has been executed continuously during the last half an hour. But under the new framework, a dedicated twenty- minute CAS (3:15–3:35 p.m. IST) would be taken into account and the orders would be finalized as per the acceptance, matching and execution of stocks via buying and selling, through a call- auction mechanism. For the first instance, it has been initiated for derivatives eligible (Future & Option Stocks) the highly liquid securities crucial for index and derivatives settlement with possibility of later expansion to wider cash market. This framework is reasoned by SEBI in phased approach on two grounds: firstly, F&O stocks form the backbone of institutional portfolios and are most relevant for index benchmarking; secondly, manipulation risks could be mitigated because of their high liquidity rates.
The practical effect can be elucidated by a short numeric contrast. Under the current VWAP approach, if a stock trades mostly between ₹100- ₹102 during the day and one among the last few trades transaction is of ₹108, the VWAP may lift modestly to about ₹103.5, thus slightly affecting the Net Asset Value (‘NAV’) and index weights. Now, under the newly introduced framework (CAS), if the 3:00- 3:15 VWAP is ₹101 with ±3% band, then the auction could clear up to around ₹104. Should a cluster of institutional orders push the clearing price to that level, ₹104 would stand as the official close, determining NAVs, takeover thresholds, and derivative settlements. This change is not minimal as a shift of ₹3-₹4 per share across millions of shares put a lot of effect on wealth transfers between acquirers, minority shareholders and passive investors. This shows how VWAP dilutes the impact of any single trade across an extended period, while on the other hand, CAS magnifies the influence by compressing decisive price formation into a narrow, highly visible window, thus creating a natural choke point for significant players.
CLOSING PRICE AS A LEGAL AND MARKET BENCHMARK
The shift is not just a mere technicality as the closing price acts as the standardized benchmark in securities regulation. For instance, under Regulation 3 of the SEBI (Substantial Acquisition of Shares and Takeovers) Regulations, 2011, open offer which has the mandate of 25% shareholding threshold is calculated with reference to the closing price. Through this, it protects the minority shareholders in control transactions. Additionally, Regulation 8 of the SEBI (Delisting of Equity Shares) Regulations, 2021 set the floor for exit consideration in delisting exercises through closing price. Moreover, even mutual fund valuations under Regulation 47 of the SEBI (Mutual Funds) Regulations, 1996 determine the NAV available to investors through the same. In this sense, the closing price performs a quasi- legal function, extending beyond market mechanics to structure substantive entitlements and liabilities. Any change in the methodology of its discovery, therefore, extends beyond technical microstructure reform like price fluctuations and engages fundamental questions of investor protection and regulatory design. Heavy order flows during the auction period can unduly influence the closing price. This makes it difficult for the small shareholders to counter the influence of large institutional trades.
One of the most analytical difficulty lies in balancing SEBI’s dual objectives: one being enhancing price accuracy and other being preventing regulatory arbitrage or market distortions. The consultation paper has acknowledged that the closing prices are often subject to marking the close, a practice where traders execute small-volume traders just before the market closes to nudge prices in the desired direction. It has been globally recognized by courts and regulators as a form of market manipulation. The fact has been reinstated in India by the Securities Appellate Tribunal through Regulation 3 of the SEBI (Prohibition of Fraudulent and Unfair Trade Practices) Regulations, 2003 which prohibits manipulative and deceptive devices. While the newly introduced framework of CAS by concentrating liquidity into a single call auction, may diminish the efficacy of last- minute trades, it also creates a new issue related to concentration of large orders to influence the equilibrium price by large players.
In the context of takeovers, the person holding 25% of company’s shares has to make an open offer to other stakeholders and that price is linked to past closing prices. So, under the new framework, the closing price could be fluctuated either up or down, depending on how big investors place their orders in that short auction window. This advantages the buyer, who is willing to take the risk of bidding aggressively in the CAS. In delisting too, price is influenced by CAS. When such a scenario persists, then prices become more volatile or controlled by the hands of a few large orders, thus leading to unfair exit value of minority shareholders. In the case of SEBI v. Cabot International Capital Corp. (2004), it was held that the main aim of securities law is to protect the investors. It means any change in reduction of fairness for investors in exit processes goes against the principal of investor protection.
CONCENTRATED ORDERS, MANIPULATION, AND INSIDER RISKS
Moreover, insider trading regulation is also affected by CAS. Under the SEBI (Prohibition of Insider Trading) Regulations, 2015, material events are reflected in stock prices with the closing price serving as a reference for detecting suspicious trading activities. When the auction price can be influenced by a dominating group of participants, then the casual link between non-public information and price movement becomes harder to establish. This results in weakening of evidentiary foundation of enforcement i.e. without adequate surveillance. If left unchecked, it could undermine the deterrent value of insider trading provisions. For minority investors, the risk is especially acute, as concentrated orders during the auction could distort prices to their disadvantage, undermining the very protections securities law aims to guarantee.
Comparative jurisprudence like European Union’s Euronext market shows that closing auctions are typically safeguarded by protective mechanism like volatility extensions, real-time extensive prices, and order imbalance disclosures. Even though, the same has been acknowledged by the SEBI’s consultation process but it does not properly consider the operability in India’s context. It is characterized by substantial retail participation, high algorithmic trading activity, and resource- constrained market surveillance. If these safeguards are not incorporated, CAS may unintentionally tilt the market towards institutional investors, thus weakening the legal and fiduciary protections afforded to minority shareholders under the Takeover Code and Delisting Regulations.
A layered approach is required to address these risks posed by CAS like requiring disclosure of large orders at the time of auction could enhance transparency and would supply regulators with empirical data to monitory systematic risks. Additionally, practices like layering, spoofing and order clustering could be incorporated in the system to protect both market integrity and equitable access as real- time surveillance system. Through the lens of economics, these measures could help reduce price imbalance, thus ensuring minority shareholders rights.
CONCLUSION
The proposed CAS marks a structural reorientation in India’s price- discovery framework, with implications that extended far beyond a technical refinement. By concentrating the price formation into a narrow window, potential choke points could be found where the dominant investors get disproportionate influence, raising questions over fairness and investor protection, especially for minority shareholders. SEBI must therefore approach CAS with strong rigorous safeguards, empirical oversight and a commitment to equitable governance, to ensure a balance between the statutory and fiduciary protections that underpins the Indian securities law.
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