Introduction of a Closing Auction Session (CAS) in the equity...

Introduction of a Closing Auction Session (CAS) in the equity cash segment replaces VWAP-based closing prices for securities with listed derivatives; SEBI mandates phased applicability, with CAS determining closing prices for derivative-underlying stocks and VWAP retained for others. CAS is a 20-minute separate session (3:153:35 pm) with specified sub-sessions, random order-entry closure, a VWAP-based reference price (3:003:15 pm) and +/-3% price bands. The equilibrium price mechanism (max executable volume; tie-breakers by unmatched quantity and proximity to reference price) governs price discovery, with market-order priority, carryover and modification rules for CTS limit orders, order-level margin requirements, disclosure obligations and SOP/operational alignment requirements for exchanges and clearing corporations.