On Day 3 after the implementation of the new Closing Auction Session (CAS), the gap between the Nifty’s 3:15 pm level and its official closing price is still grabbing attention, though the gap is reducing.
For the third consecutive trading session since the new settlement mechanism was introduced for Futures & Options (F&O) eligible cash stocks, the Nifty’s final closing level was different from where it stood at 3:15 pm.
On Wednesday, the gap narrowed compared with the previous two sessions.
The benchmark Nifty was at 24,570 at 3:15 pm. However, after the Closing Auction Session concluded, the index finally settled at 24,624.65, around 55 points higher than its regular market close.
Sensex stood at around 78,502 at 3:15 pm before ending the session at 78,581, a gain of nearly 79 points during the auction period.
The difference, however, was much smaller than the previous two sessions. On the first day of the new system, the Nifty’s closing price jumped by nearly 200 points after 3:15 pm, while on the second day the difference stood at around 150 points.
Somil Mehta, Head of Retail Research at Mirae Asset ShareKhan said, “The narrowing gap between the 3:15 pm Nifty level and the final closing value shows that market participants are gradually adapting to the Closing Auction Session. As participation increases, price discovery will improve, making closing prices more accurate, transparent and less vulnerable to end-of-day price manipulation over the long term.”
What is changing after 3:15 pm?
The National Stock Exchange (NSE) has introduced the Closing Auction Session (CAS) for stocks in the equity cash segment that are eligible for Futures & Options trading. Stocks not eligible for F&O continue continuous trading until 3:30 pm.
Under the revised framework, normal continuous trading for F&O-eligible cash stocks ends at 3:15 pm. After that, the exchange conducts a 20-minute auction session (3:15 pm to 3:35 pm) divided into distinct phases: reference price calculation (3:15–3:20 pm), an order entry period (3:20–3:30 pm), and order matching (3:30–3:35 pm). During this window, buy and sell orders are matched to arrive at a single equilibrium closing price, which is now used as the official closing price for these stocks and benchmark indices.
It is important to understand that while continuous trading for eligible underlying cash stocks ends at 3:15 pm, actual F&O derivative contracts (Stock & Index Futures and Options) continue continuous trading until 3:40 pm to give market participants time to hedge and manage positions during the CAS window.
As a result, investors may now notice that the final closing value of the Nifty and Sensex is different from the level seen at exactly 3:15 pm.
Technical picture: Consolidation continues
Sudeep Shah, Head – Technical and Derivatives Research at SBI Securities, said “Nifty opened with a gap-up but encountered strong resistance in the 24660–24680 zone, following which it gradually drifted lower through the session to close at 24570 (3:15 PM). However, the closing price post the closing auction session came at 24625, 55 points higher.”
Shah added that the market is currently taking a breather after its recent rally.
Shah noted, “On the daily chart, the index formed a small body bearish candle with a noticeable lower wick. Over the last three sessions, Nifty has been consolidating within the 24,774–24,428 range, indicating a phase of pause after the recent up move. Despite this consolidation, the index continues to trade above its key short-term and long-term moving averages, keeping the broader trend positive. Meanwhile, the ADX is gradually trending higher, indicating strengthening trend momentum.”
Why did markets lose momentum during the day?
Although the market started the session on a positive note, gains gradually faded as investors reacted to rising crude oil prices and renewed geopolitical concerns.
Vinod Nair, Head of Research, Geojit Investments, said, “The RBI’s MPC has maintained the status quo while marginally upgrading FY27 GDP growth projection, citing a resilient domestic economy. Additionally, annual inflation estimates were lowered, indicating the governor’s open minded approach, which suggested an optimistic view though further policy action would depend on data.
“Consequently, a rise in crude prices following renewed concerns over escalating tensions in West Asia, led Indian markets, which had opened strongly, to gradually move lower during the course of the session. Defying the broader market trend, realty and auto stocks outperformed on strong demand expectations ahead of festive season and supportive financing conditions, while metal stocks gained on the back of an improved GDP growth outlook and robust domestic demand,” added Vinod Nair.
Bank Nifty also saw a post-auction jump
The Bank Nifty followed a similar pattern.
According to Shah, “Bank Nifty opened with a gap-up but faced stiff resistance in the 57920–57940 zone during the first hour of trade. The index subsequently drifted lower through the session to close at 57,630 (3:15 PM). However, the closing price post the closing auction session came at 57740, 110 points higher.”
He added, “Following its consolidation breakout on 3rd August, the index has struggled to sustain at higher levels. However, it has managed to hold above its 20-day EMA over the past two sessions, suggesting that the near-term bullish structure remains intact despite the ongoing profit booking.”
While the gap between the 3:15 pm level and the final settlement has narrowed from Day 1 and Day 2, the third straight session with a higher auction close suggests that traders are still adjusting to the new Closing Auction Session framework.