Why collect orders first?
Overnight, people read results, change their minds and prepare orders. If the opening price came from whichever tiny trade happened first, it could represent very little of that demand.
A call auction collects orders, then seeks one price at which the greatest quantity can trade. Buyers and sellers must still have compatible prices. An auction does not make every order executable.
The continuous session works differently: an incoming order can match immediately against eligible resting orders. That is the price-time queue you met in 01.04.01.
Choose the moment
These are NSE cash-market sessions. All times are Indian Standard Time. Tap each phase.
One clock does not describe every security. Special sessions and exchange notices can change the timetable.
Try an opening price on paper
Use a separate hypothetical Bharat Foods auction, not the historical purchase. There are only three orders: a buyer wants 10 shares at up to ₹500; another wants 10 at up to ₹499; a seller offers 15 at no less than ₹499.
At ₹500, only 10 shares of demand qualify. At ₹499, all 20 qualify against 15 offered. So ₹499 allows 15 shares to trade, the maximum. Both sides of those trades receive the same auction price.
The ₹500 limit buyer can therefore pay ₹499: a limit is the worst acceptable price, not an instruction to pay exactly that amount. With 20 wanted and 15 offered, some demand remains unfilled. Where multiple prices tie, the exchange applies further imbalance and reference-price rules.
In that hypothetical auction, you bid up to ₹500. The auction price is ₹499 and your order is allocated shares. What do you pay per share?
The two 2026 changes
Pre-open: from 09:00–09:05, limit and market orders may be entered, changed or cancelled. Thereafter only limit orders can be entered, changed or cancelled; market orders are locked. Collection closes randomly between 09:08 and 09:10, followed by matching and a buffer before 09:15. Market orders have priority over limit orders in auction matching.
Closing auction: the current first phase covers cash shares with derivatives available. Between 15:15–15:20 the exchange transitions and calculates a reference price. Order entry starts at 15:20, market orders lock at 15:25, and collection ends randomly between 15:28–15:30. Matching finishes by 15:35. The post-close session is 15:50–16:00.
For non-CAS shares, the closing price generally uses the volume-weighted average of the last half-hour's trades, with exchange fallback rules when trades are absent. It need not equal the last traded price. A post-close session trades at an already determined closing price; it does not discover a fresh one.