Neutral impactEconomy
Market chaos after CAS: What exactly is Sebi reviewing and will it stop expiry-day wild swings?
Economic Times 1 hr ago·4 Sept 2026, 8:42 am
The Indian stock market has recently experienced sharp volatility on expiry days, prompting the Securities and Exchange Board of India (Sebi) to launch a review. The regulator is specifically examining the methodology used to determine the settlement price for derivatives, which is currently linked to the Closing Auction Session (CAS). This session involves a brief window where orders are matched to set the day's final price. Sebi is now assessing whether this specific link is the primary driver of extreme price swings seen during these critical trading periods.
This review matters to investors because expiry-day volatility can lead to unexpected losses, especially for those holding positions in the broader market. If Sebi decides to revise the framework, it could lead to a more stable settlement process that reduces extreme price movements without completely removing the normal mechanisms that drive market activity. Investors should watch for the regulator's final recommendations, which could signal a shift in how derivative prices are calculated in the future.
Moving forward, market participants will be closely monitoring Sebi's consultation papers and any proposed changes to the CAS rules. A shift away from using CAS closing prices for settlement could smooth out the wild swings seen recently. However, it is important to note that a revised framework is likely to maintain the core purpose of the auction while aiming to dampen excessive volatility, rather than eliminating it entirely.
Excerpt from Economic Times
Sebi’s review of derivative settlement price methodology could reduce sharp expiry-day swings linked to the Closing Auction Session (CAS). Analysts expect the regulator to consider delinking derivative settlements from CAS closing prices rather than scrapping the mechanism. However, a revised framework may curb…Read the original at Economic Times
Key takeaways
- Category: Economy.
- Assessed as a significant, market-relevant update.
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A meaningful update worth tracking. Use the price and stock snapshot to gauge how the market is responding.
