Block Deals And Bulk Deals: Why Big Institutional Trades Move Sentiment

Last Reviewed and Updated: 17 Aug 2026

A bulk deal happens inside the regular, continuous trading session, triggered when a single client buys or sells at least 0.5% of a company's total listed shares in a single day, executed through the normal order book alongside every other trade happening that moment.

A block deal is structurally different: a single, privately negotiated transaction between two parties, executed in a separate, dedicated trading window set apart from regular hours, at an agreed price rather than through continuous order matching.

	Bulk Deal	Block Deal
Where it happens	The regular trading session, in the normal order book	A separate, dedicated window outside continuous trading
What triggers it	A single client trading at least 0.5% of a company's total listed shares in a day	A single negotiated transaction meeting a minimum value threshold
How the price is set	Through normal, continuous order matching	Privately agreed between the two parties, within a set price band
Who typically executes these	Institutions, large funds, and high net worth individuals	Mutual funds, insurance companies, foreign investors, and high net worth individuals

The Block Deal Window, After October 2025's Overhaul

SEBI's revised framework, following recommendations from a dedicated Working Group and the Secondary Market Advisory Committee alongside public consultation, changed several specifics of how the block deal window actually operates.

The minimum order size required to use the window rose from Rs 10 crore to Rs 25 crore, restricting it to genuinely large institutional trades. Two windows now run each trading day, a morning session from 8:45 am to 9:00 am, referencing the previous day's closing price, and an afternoon session from 2:05 pm to 2:20 pm, referencing the volume weighted average price of trades between 1:45 pm and 2:00 pm.

Orders must fall within 3% of that reference price, widened from the earlier 1% band, giving genuinely more flexibility to negotiate a price than the previous rule allowed. Every trade executed in the window must now result in actual delivery, removing any ambiguity about whether a block deal could be used for a same day, non delivery based position.

	Before December 2025	From December 7, 2025
Minimum trade size	Rs 10 crore	Rs 25 crore
Permitted price band	1% of the reference price	3% of the reference price
Delivery requirement	Less explicitly mandated	Every window trade must result in actual delivery

Block deals remain restricted to stocks eligible for the futures and options segment with a minimum market capitalisation of Rs 500 crore on the NSE, with BSE also permitting constituents of the BSE 500 index, keeping the window limited to genuinely large, liquid companies rather than the entire listed universe.

A negotiation that happened privately is not the same as information that stays private. Both bulk and block deals are disclosed to the exchange, and that disclosure is the entire reason retail investors get to see what large money just did.

Why These Trades Move Sentiment

Both mechanisms are read by the market as signals of institutional conviction, since the typical counterparties, mutual funds, insurance companies, foreign institutional investors, and high net worth individuals, are assumed to act on more research and more capital than an average retail trade.

Bulk deals happen visibly inside the regular order book, meaning they can move a stock's price directly and immediately, in front of every other participant trading that stock at the same moment.

Block deals, though privately negotiated, are still disclosed to the exchange shortly after the window closes, so the identity of the trade, if not always the identity of the parties, becomes public information the same day.

The scale involved is genuinely large: in 2025, promoters, private equity firms, and venture capital investors sold shares worth roughly Rs 2.34 lakh crore through block deals on NSE and BSE combined.

What A Large Trade Does Not Necessarily Mean

Reading a single block or bulk deal as a clean, directional signal risks mistaking a routine ownership event for a market call.

A large sale can reflect a promoter raising personal liquidity unrelated to the company's prospects, a private equity or venture capital investor exiting once a lock in period expires, covered in more depth in our earlier article on IPO lock in periods, routine portfolio rebalancing by an institutional fund, or forced buying and selling triggered by an index reconstitution that has nothing to do with anyone's view on the stock itself.

The trade is real and the disclosure is genuine. The story attached to it in market commentary is often a guess filled in after the fact.

Where To Actually Check This Data

NSE and BSE both publish bulk and block deal disclosures directly on their own websites, typically available after market hours the same trading day, showing client codes, whether the trade was a buy or a sell, the quantity, the price, and the company involved.

This is genuinely public, freely available data, not something reserved for institutional research desks, and checking it directly is more reliable than relying on a secondhand summary that may not specify which of the two mechanisms actually produced a given headline.

Note: SEBI overhauled the entire block deal framework through a circular dated October 8, 2025, with the revised rules taking effect December 7, 2025. The minimum trade size moved from Rs 10 crore to Rs 25 crore, and the permitted price band widened from 1% to 3%. Any description of block deal rules that does not reflect this specific change is describing the framework as it stood before this revision, not the one currently in force.

This article is for general informational purposes only and does not constitute investment advice. Block deal and bulk deal thresholds, timings, and price bands are set by SEBI and the stock exchanges and are subject to change; the framework described here reflects the rules in force following the December 2025 revision, as understood in August 2026. Confirm current thresholds and timings directly on the NSE or BSE website before relying on them, and consult a qualified financial adviser before making any investment decision.

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