Archive · 31 Aug 2026
Somaiya urges SEBI to suspend and redesign CAS
Kirit Somaiya wants India’s market regulator to review a new trading process called CAS.
On August 27, the Sensex moved down by more than 2,200 points and then recovered about 2,000 points in the last minutes of trading.
This happened during the first monthly derivatives expiry after CAS began.
Somaiya is concerned that there may not be enough buyers and sellers after 3:15 p.m.
Under CAS, regular continuous trading ends at 3:15 p.m.
and a separate auction is used to determine closing prices.
Equity derivatives continue trading until 3:40 p.m.
He wants CAS paused, redesigned, and investigated before being brought back.
Former BJP MP Kirit Somaiya asked SEBI to suspend and redesign the Closing Auction Session framework.
The Sensex reportedly fell more than 2,200 points and recovered about 2,000 points between 3:20 p.m. and 3:30 p.m. on August 27.
The sharp movement occurred during the first monthly derivatives expiry after CAS was introduced.
Somaiya cited possible liquidity problems after 3:15 p.m., when continuous trading in CAS securities ends.
He also called for an inquiry into whether the volatility reflected a system weakness or deliberate interference.
- Who
- Former BJP MP Kirit Somaiya wrote to Securities and Exchange Board of India Chairman Tuhin Kanta Pandey.
- What
- Somaiya urged SEBI to suspend, redesign, and investigate the Closing Auction Session framework.
- When
- The market movement occurred between 3:20 p.m. and 3:30 p.m. on August 27, during the first monthly derivatives expiry after CAS was introduced.
- Where
- The episode occurred in the Indian stock market; Somaiya’s letter was addressed to SEBI in Mumbai.
- Why
- He cited unusual volatility, possible post-3:15 p.m. liquidity shortages, and concerns about weaknesses or deliberate interference in the CAS framework.
- Market movement
- The Sensex reportedly fell by more than 2,200 points and recovered around 2,000 points.
- Timing
- The sharp movement took place between 3:20 p.m. and 3:30 p.m. on August 27.
- Trading context
- The episode occurred during the first monthly derivatives expiry since CAS was introduced.
- Continuous trading cutoff
- Continuous trading in CAS securities ends at 3:15 p.m.
- Auction mechanism
- After 3:15 p.m., the market moves into a separate closing auction.
- Derivatives trading
- Equity derivatives continue trading until 3:40 p.m.
- Requested action
- Somaiya proposed temporarily suspending CAS and reintroducing it after a redesign.