The closing auction session (CAS) that determines the final price of index futures and options has become a flashpoint every month‑end. Sharp moves in the Nifty and Sensex on expiry have often been traced to the way settlement prices are derived from the CAS, prompting traders to unwind positions in a narrow time window and sometimes triggering volatility spikes that spill over to spot equities. SEBI has now opened a formal review of the settlement‑price methodology.
Sources say the regulator is weighing a partial delink – keeping the CAS for price discovery but using an alternative reference for derivative settlement – rather than scrapping the auction altogether. Market participants expect the revised framework to smooth out extreme swings while preserving the normal expiry‑day price adjustments that help align futures with the underlying market. For the average retail investor, a calmer expiry could mean less abrupt price gaps in the Nifty 50 and a reduced need to monitor intra‑day movements solely for contract roll‑overs.
Portfolio managers may adjust hedging strategies, and systematic traders could see tighter spreads. However, the underlying volatility risk will not disappear; investors should continue to use stop‑losses and maintain diversified exposure. SEBI is expected to table its final proposal in the coming weeks, and market watchers will gauge the impact on liquidity and volatility before the next expiry cycle begins.