The Sensex plunged greater than 2,000 factors inside minutes through the CAS on Thursday, falling from round 77,200 at 3:17 pm to almost 74,983 at 3:23 pm. The index subsequently recovered a few of its losses however nonetheless ended the day 539 factors, or 0.7%, decrease at 76,934.
India modified how closing costs are decided from August 3. As a substitute of calculating the shut utilizing the volume-weighted common value (VWAP) through the ultimate half-hour of buying and selling, exchanges launched a brief Closing Public sale Session, through which purchase and promote orders are aggregated, and a single equilibrium value is found.
In a communication looking for consideration to the August 27 motion, Somaiya requested whether or not the sharp intra-session swing pointed to a weak spot within the CAS mechanism and known as for an inquiry and motion.
“On 27 August, over the last 12 minutes of buying and selling at NSE/BSE, the Sensex crashed over 2,200 factors after which recovered 2,000 factors,” Somaiya stated, asking whether or not “it’s a weak spot within the CAS system”.
He additionally requested whether or not the transfer might have been linked to any deliberate try to undermine the implementation of CAS, whereas calling on SEBI to look at the matter.
“SEBI should not take this CASUALLY,” he stated. “If it’s a weak spot, then the officers who drafted it ought to owe a proof. Whether it is achieved knowingly, is it wholesome? Is it sabotage to cease implementation of CAS?””Shockingly, such issues occurred through the course of of getting a wholesome system,” Somaiya stated, including that he needed “not solely inquiry however motion additionally.”
Liquidity issues after 3:15 pm
Alongside together with his communication, Somaiya shared an remark that attributed the sharp motion partly to an absence of liquidity after 3:15 pm.
“The basic drawback can also be – there is no such thing as a depth as a consequence of lack of liquidity after 3.15. All now commerce earlier than 3.15 pm. Any one that desires to buy/sale after 3.15 pm does not discover liquidity and therefore volatility,” the remark stated.
The accompanying be aware proposed quickly suspending CAS and reintroducing it after a redesign, citing a number of issues round liquidity, value discovery and the interplay between the money and derivatives markets.
Beneath the current framework, steady buying and selling in CAS securities ends at 3:15 p.m., after which the market strikes right into a separate public sale. Fairness derivatives, nevertheless, proceed to commerce till 3:40 p.m.
The be aware argues that this construction removes continuous-market liquidity earlier than the public sale begins. At 3:15 p.m., the continual price-discovery mechanism is stopped and changed by the public sale order guide, which the be aware describes as materially shallower.
The be aware additionally raises issues concerning the fragmentation of closing liquidity between NSE and BSE. It factors out that the identical safety can endure separate closing auctions on the 2 exchanges, with separate order books, imbalances and doubtlessly completely different equilibrium costs.
In keeping with the be aware, on the primary day of CAS, reported public sale turnover was roughly Rs 1,276 crore on NSE in contrast with round Rs 10.8 crore on BSE, a distinction of greater than 100 instances.
It argues that whereas the aim of a closing public sale is to pay attention liquidity, separate auctions on the 2 exchanges might as an alternative fragment liquidity.
Questions over closing-price formation
The be aware additionally questions whether or not a comparatively small quantity of public sale buying and selling can present a sufficiently sturdy value for a a lot bigger pool of capital whose worth is set utilizing the official closing value.
The closing value feeds into mutual fund NAVs, portfolio valuations, index closing ranges, passive-fund monitoring, mark-to-market valuations, by-product settlement economics and efficiency measurement, in accordance with the be aware.
It subsequently argues that the framework ought to think about minimal liquidity and market-quality situations earlier than an public sale value mechanically turns into the official shut.
One other concern pertains to the CAS’s ±3% public sale band. The be aware argues that such a spread might lead to a major change within the marked-to-market worth of huge firms even when the amount truly matched within the public sale represents solely a small portion of the corporate’s excellent shares.
For a corporation with a Rs 5 lakh crore market capitalisation, the be aware estimates {that a} 3% motion would change its marked market capitalisation by roughly Rs 15,000 crore.
It proposes a extra conservative, dynamic collar that expands solely when supported by substantial two-sided public sale liquidity.
Money and derivatives function on completely different timelines
The be aware additional highlights the completely different buying and selling timelines for the money and derivatives markets. Whereas steady money buying and selling for CAS securities stops at 3:15 p.m., fairness derivatives proceed buying and selling past the public sale.
In keeping with the be aware, this implies futures and choices can proceed to mirror altering info and expectations even after the underlying money safety has ceased steady value discovery.
It argues that this weakens the conventional cash-futures arbitrage mechanism on the level when the official closing benchmark is being established.
Concern over skinny liquidity and expiry-day volatility
The be aware additionally argues that insufficient CAS liquidity might create a self-reinforcing cycle. If giant establishments understand liquidity within the public sale as inadequate, they could execute earlier than 3:15 p.m., additional decreasing public sale liquidity. Decrease liquidity might then enhance value affect and execution uncertainty, discouraging participation additional.
The be aware calls this a “adverse liquidity flywheel”: low liquidity will increase public sale affect, weakens execution certainty, reduces participation and additional drains liquidity.
“Participation is subsequently partly an consequence of fine market design, not merely a
prerequisite that may be assumed to emerge over time,” it stated.
(Disclaimer: Suggestions, ideas, views and opinions given by the specialists are their very own. These don’t signify the views of Financial Instances)




