How 14 Minutes of Closing Auction Trading Reversed Six Hours of Flat Markets? – 10th Sep
The Sensex traded in a narrow 282-point band for nearly six hours on Thursday's weekly options expiry day, then swung 4,655 points in just 14 minutes once the closing auction session (CAS) opened — moving more in that window than during the entire rest of the day. The Sensex briefly indicated a level 1,078 points higher before settling at 74,902.59, while the Nifty 50 saw a similar spike before closing only marginally higher; without the CAS swing, both indices would have logged a fourth straight day of losses. Traders and market-structure experts said far out-of-the-money options saw a surge in contract volumes in the final 15 minutes, with some strikes' volumes jumping nearly 50-60%, as speculators increasingly bet on settlement-price uncertainty during this window.
