2 weeks ago
SEBI's Closing Auction Session Sparks Debate Over Market Readiness
When people buy and sell shares in the stock market, the price at the end of the day used to be simply the last price a share was traded at.
India's market regulator, SEBI, changed this with a new system called the Closing Auction Session.
Now, the final closing price is decided in a special mini-auction held after regular trading stops.
Regulators say this makes the closing price fairer and less likely to be manipulated.
But many traders were surprised by the change and complained about strange price moves near the close, because the final price can differ from the price right before trading ends.
Some traders even talked about boycotting trading for one day to show their frustration.
SEBI says the new system is here to stay and has asked brokers to teach investors how it works.
The article says the reform may be a good idea, but India should have prepared better, with more testing and education before starting it.
It also says SEBI should study the data to see whether the auction truly works well.
Good ideas need good planning, the article concludes.
India's new Closing Auction Session (CAS), which sets closing prices through a final auction, met the market on August 3.
Within days, traders complained of sharp, unfamiliar movements around the close and launched a social media campaign calling for a one-day trading boycott.
SEBI ruled out a rollback and asked brokers to educate investors about the new system.
SEBI says CAS improves price discovery, provides a transparent closing price, helps large institutional orders, and reduces tracking error for passive funds, citing international practice.
The article, written by a retired IRS officer and former chief of surveillance at SEBI, argues consultation and investor education should have preceded implementation and that the rollout needs empirical scrutiny.
- Who
- SEBI, India's securities market regulator, introduced the system for investors, brokers and traders, who have responded with complaints and a boycott call.
- What
- The introduction of the Closing Auction Session (CAS), a new mechanism for determining stock closing prices, which has drawn criticism from traders.
- Where
- India's cash equity market.
- When
- August 3, when CAS met the market; complaints emerged within days of its launch.
- Why
- SEBI wants to improve price discovery, provide a more transparent closing price, facilitate large institutional orders and help passive funds reduce tracking error, matching practices in major international markets.
Traders and Critics
SEBI (Regulator)
Adequacy of preparation
Traders and Critics
Consultation was 'notional'; investor education, mock trading and exchange simulations should have preceded implementation rather than following complaints.
SEBI (Regulator)
SEBI consulted through papers in 2024 and 2025 and its Secondary Market Advisory Committee, and has asked brokers to educate investors about the new system.
Whether the reform works
Traders and Critics
Sharp, unfamiliar movements around the close raise doubts about price discovery and cash-derivatives interaction, though the article says it is too early to call CAS defective.
SEBI (Regulator)
A closing auction can aggregate market interest, improve price discovery, provide a transparent closing price and help passive funds reduce tracking error, as seen in major international markets.
Rollback of the mechanism
Traders and Critics
Traders' social media campaign called for a one-day trading boycott to protest the rollout.
SEBI (Regulator)
SEBI has made clear there will be no rollback of the Closing Auction Session.
Key facts
- Regulator
- Securities and Exchange Board of India (SEBI)
- New mechanism
- Closing Auction Session (CAS) for determining closing prices
- Implementation date
- August 3
- SEBI's stance
- No rollback; brokers instructed to educate investors
- Traders' response
- Complaints about sharp moves; social media call for a one-day trading boycott
- Consultation process
- Consultation papers in 2024 and 2025; deliberations by the Secondary Market Advisory Committee
- Stated objectives
- Better price discovery, transparent closing price, facilitate institutional orders, reduce tracking error for passive funds
- Author
- Retired IRS officer and former chief of surveillance at SEBI
Sources
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