How to Read a Block Deal Disclosure (2026 Rules)

A block deal disclosure is the same-day record the exchanges publish naming who traded a large block of a company's shares, in what quantity, and at what price. Reading one correctly means knowing three things: which window it went through, what the current thresholds are, and what the client name column does not tell you. The thresholds changed recently, so a lot of published guidance on block deal disclosure is now out of date.

What changed in December 2025

SEBI issued circular SEBI/HO/MRD/POD-III/CIR/P/2025/134 on 8 October 2025, reviewing the block deal framework. It took effect 60 days from issuance, on 7 December 2025. Three parameters moved.

The window timings were retained: a morning window from 8:45 AM to 9:00 AM referenced to the previous day's closing price, and an afternoon window from 2:05 PM to 2:20 PM referenced to the volume weighted average price of trades between 1:45 PM and 2:00 PM.

The practical consequence for anyone comparing periods: a block deal count from 2024 and one from 2026 are not measuring the same thing. Trades between 10 and 25 crore rupees that would once have appeared in the block window now execute elsewhere.

How to read the fields

A block deal disclosure carries four things the exchange publishes after market hours: scrip name, client name, quantity, and traded price.

Client name. This is the trading client, which is often but not always the beneficial owner. A fund house may trade through a scheme name; a foreign investor may appear under a custodial or sub-account name. Treat the name as an identifier to be matched carefully, not as a settled answer about who owns what.

Quantity and price. Multiply them and check the result clears 25 crore rupees. If it does not, you are probably looking at a bulk deal rather than a block deal, which is a different disclosure with a different trigger.

Direction. Each block deal has a buy side and a sell side, and both are disclosed. A common error is counting a single trade twice by treating the buy leg and the sell leg as two separate events.

Date and window. The reference price differs between the morning and afternoon windows, so the price relative to the day's close reads differently depending on which window was used.

Block deal or bulk deal?

These are separate regimes and the disclosures are separate too.

A bulk deal is triggered by size relative to the company: a single client's trades exceeding 0.5 percent of the listed shares in a day, executed in the normal market. A block deal is triggered by absolute value, at least 25 crore rupees, executed in the dedicated window at a negotiated price. A single large transaction can generate both records. For the full comparison see bulk deals vs block deals and how to track bulk and block deals.

What a block deal disclosure does not tell you

It records that a trade happened at a price on a date between named clients. It does not record intent. A sale can be portfolio rebalancing, a fund redemption, a promoter raising money, a lender selling after a pledge invocation, or a stake sale agreed months earlier.

It is also a point in time, not a position. To see whether an institution's overall holding actually moved, the quarterly shareholding pattern is the record that settles it, because a single block can be offset by ordinary market activity across the quarter.

Flock reports bulk and block deals as NSE and BSE publish them, each stamped with its trade date and linked back to the exchange. The mandatory-delivery rule introduced in December 2025 means these are now unambiguously transfers of ownership rather than positions that might be reversed the same day. What that means for any holding is your call to make.