Post-Market Session
The 20-minute closing call auction (3:40–4:00 PM IST) on NSE and BSE that lets equity investors transact at the day's official closing price after regular trading has ended.
Definition
The post-market session — also called the closing session or post-close session — is a call auction window on NSE and BSE that runs from 3:40 PM to 4:00 PM IST, after the regular continuous trading session ends at 3:30 PM. During this session, investors can place orders for equity cash segment stocks at the official closing price determined by the exchange. This closing price is computed as the volume-weighted average price (VWAP) of the last 30 minutes of continuous trading (3:00–3:30 PM), not simply the last traded price. Unlike global after-hours markets, the post-market session in India does not allow price discovery — all matched orders execute at the single pre-determined closing price, making it a structured way to transact at a known, auditable benchmark price. It is not available for futures and options, which close at 3:30 PM.
Why it matters
Large institutional investors — mutual funds, insurance companies, and foreign portfolio investors (FPIs) — often need to execute significant equity block trades at the official closing price (NAV benchmark, performance benchmarking, index replication). The post-market session provides a structured venue to do this without impacting prices during regular hours. For retail investors, the session offers a convenient window to transact after the bulk of intraday volatility has passed, at a stable, pre-known price. From an F&O perspective, the closing price of the underlying equity established during the regular session (via the 3:00–3:30 PM VWAP) becomes the reference for mark-to-market calculations for stock futures and for determining the intrinsic value of stock options at expiry for physical settlement purposes.
How it works
The post-market session runs in two phases. From 3:40 to 3:50 PM, order entry, modification, and cancellation are permitted. Only limit orders at the closing price are accepted — you cannot place orders above or below the closing price. From 3:50 to 4:00 PM, orders are matched at the closing price and confirmed. Unmatched orders are cancelled; they do not carry over to the next trading day's pre-open session. The session is available on both NSE and BSE and applies to equities in the normal trading segment. Intraday orders, bracket orders, cover orders, and any derivatives contracts cannot be placed during this window. The closing price used as the execution price is the same VWAP-based closing price published by the exchange at 3:30 PM, making it fully transparent and replicable.
Example
Suppose the VWAP-based closing price of a hypothetical company, PQR Ltd, is computed as ₹750 at 3:30 PM after the regular session closes. During the post-market session (3:40–3:50 PM), a long-term investor places a buy order for 500 shares of PQR Ltd. The order is accepted at ₹750. At 3:50 PM, if there is sufficient sell-side supply at ₹750, the 500 shares are matched and confirmed. The investor's demat account will be credited with 500 shares on T+1 settlement at ₹750 each, totalling ₹3,75,000 plus applicable charges — regardless of any after-hours price signals from US or Asian markets that may have moved between 3:30 PM and the time the order was placed.
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