Stock Market · Introduction to Stock Markets

Pre-open session

From 9:00 to 9:15 AM, the market is not open yet. It's in a different mode: price discovery.

The three phases

1. 9:00 AM → 9:08 AM. Order collection. Place, modify, or cancel orders freely. Nothing executes yet. All orders sit in a queue.

2. 9:08 AM → 9:12 AM. Price discovery. The exchange takes all buy and sell orders from the first 8 minutes and calculates the price at which the maximum number of shares can trade. That becomes the opening price.

3. 9:12 AM → 9:15 AM. Buffer. Orders locked. System prepares for live trading.

9:15 AM: market opens. Pre-open orders execute first.

Why this exists

If overnight news drops (RBI decision at 10 PM, global crash, big earnings after close), markets need a controlled way to absorb that information before live trading goes chaotic. Without the pre-open session, the 9:15 AM open would be a price-discovery explosion.

> RBI announced an emergency rate cut after 3:30 PM in March 2020. The pre-open session next morning showed massive buying interest. The opening price reflected the good news before a single retail market order fired.

Practical tip

If you want to buy at or near the open, place a limit order in pre-open, not a market order. A market order at 9:15 in a volatile session can fill ₹5–10 above where you expected.

8 minutesYour window to place orders before price is set

0Trades that execute during order collection phase

Takeaway. The pre-open session sets the opening price using accumulated overnight demand, not live trading.