Block Deal vs Bulk Deal: What's the Difference?

Open the business news any evening and you'll see two phrases come up again and again — block deal and bulk deal. For most retail investors, they sound interchangeable. They're not. The two are governed by different SEBI rules, happen at different times of day, and tell you slightly different things about what India's biggest investors are doing with their money.

This article is the beginner-friendly breakdown — what each one is, how they actually work, why they exist, and the one mistake retail investors make when they try to trade on this information.

The Quick Comparison

If you're in a hurry, here's the whole article in one table. The rest of the piece unpacks each row in plain English.

Keep reading and we'll go row by row. If you only remember one thing from this article: block deals are pre-arranged wholesale trades; bulk deals are open-market retail trades that just happen to be very big.

What Is a Bulk Deal?

A bulk deal is the simpler of the two to understand because there's nothing special about how it executes. It happens in the same market, on the same screen, at the same prices that you and I trade at.

Here's the SEBI definition, in plain English: if a single client buys (or sells) more than 0.5% of a company's listed equity shares in a single trading day, that's a bulk deal. The 0.5% can come from one trade or many trades — it's the daily total that counts.

Take a concrete example. Say Tata Motors has 368 crore equity shares listed. 0.5% of that is roughly 1.84 crore shares. If a foreign fund buys 2 crore Tata Motors shares across multiple trades on the same day — through the regular order book, just like you'd place a buy order — that crosses the threshold. The broker handling those trades has to report it to NSE by the end of the day, and NSE puts it out publicly after the close.

Three things matter about how this works:

One — it's not pre-arranged. The buyer puts orders into the same order book as everyone else. They might use a smart algorithm to break the order into smaller chunks so it doesn't move the price too much. They might use VWAP execution. But ultimately, every match happens against whoever's on the other side at that moment.

Two — it's visible while it's happening. The volume shows up on your chart. The trades show up in the broker's terminal. You don't know who is buying or selling until after the market closes, but you can absolutely see something is going on.

Three — the broker has to disclose. If the deal happened in a single transaction, the broker must inform the exchange immediately. If it happened across multiple transactions during the day, the broker has up to one hour after market close to file. The exchange then publishes the details — name of the stock, name of the client, total quantity, average price, and which side they were on.

What Is a Block Deal?

A block deal is a different beast. It's pre-arranged, off the main market, between two specific parties who already agree on the price and the size before the trade hits the screen.

Think of the regular stock market as a busy retail bazaar — anyone can walk in and shout a bid. The block deal window is the back room where two wholesalers shake hands on a deal worth tens of crores, and only after they shake hands does the transaction become public.

Here are the rules, all of them, as they stand today after SEBI's October 2025 overhaul:

Minimum size: ₹25 crore in a single trade. This was raised from ₹10 crore by SEBI's circular dated October 8, 2025, and the new threshold became effective 60 days later. So as of December 2025, anything under ₹25 crore in the special window simply doesn't qualify.

Two windows per trading day:

The morning window runs from 8:45 AM to 9:00 AM — a full 15 minutes before regular trading opens. The reference price during this window is the previous day's closing price.

The afternoon window runs from 2:05 PM to 2:20 PM. The reference price here is the volume-weighted average of all trades in that stock between 1:45 PM and 2:00 PM — so it captures the live market mood, not yesterday's snapshot.

Price band of ±3% around the reference. Earlier this was ±1%, which was so tight that genuine institutional trades sometimes couldn't get done if the stock had moved overnight. SEBI widened it to ±3% in the same October 2025 circular to give participants more room to actually execute.

Single-shot execution. The order either matches in full or it doesn't match at all. There's no partial fill, no carrying over to the next window. If you placed a ₹40 crore order in the morning window and it didn't match, you start over in the afternoon — fresh order, fresh reference price.

Delivery is compulsory. You cannot square off a block deal intraday. The shares actually have to move from the seller's demat to the buyer's demat. This rule exists to stop people from gaming the window for speculative trades — block deals are supposed to be genuine ownership changes, not bets.

Same-day public disclosure. The exchange publishes everything after market hours — name of the stock, names of the client and counterparty, quantity, traded price. By the time the next day opens, the entire market knows what happened.

The Bazaar and the Back Room

The cleanest way to think about the difference: bulk deals happen in the regular market; block deals happen around it.

A bulk deal is a giant retail trade. The investor walks into the same shop everyone else uses, asks for a giant quantity, and pays whatever the shop charges — adjusted second by second as the queue moves. The trade is loud. The bigger it is, the more the price wobbles while it's going through.

A block deal is a wholesale transaction in a separate room. The buyer and seller already know each other's price and size before they walk in. They use the room only to make the transaction legal and recorded. The main market never sees it happen — it just sees the result, after the fact, in the day-end disclosure.

The wholesale-vs-retail framing also explains why each mechanism exists. A mutual fund that needs to buy ₹200 crore of Reliance can't just dump that order into the regular market — the moment the order book sees it, the price runs away. Either they break it into a thousand small chunks over many days (which is what they typically do for bulk-deal-sized trades), or they find a counterparty who's willing to sell ₹200 crore at a fair price, and they shake hands in the back room.

How the Rules Evolved

If you've read older articles on block deals, you might see numbers that don't match this article — ₹5 crore minimum, ±1% band, single morning window. Those weren't wrong when they were written; the rules have changed three times. Here's the short version.

• Sept 2005

  The block deal window is born

  SEBI introduces the block deal mechanism through circular MRD/DoP/SE/Cir-19/05. A single morning window of 35 minutes, minimum order size ₹5 crore or 5 lakh shares, price band ±1%. The goal: let institutions move large stakes without disrupting the main market.

• Oct 2017

  Two windows, higher minimum

  SEBI circular CIR/MRD/DP/118/2017 splits the block deal window into morning (8:45-9:00 AM) and afternoon (2:05-2:20 PM), and raises the minimum order size to ₹10 crore. The price band of ±1% stays. The reform takes effect January 2018.

• Oct 2025

  The 2.5x jump

  SEBI's October 8, 2025 circular (SEBI/HO/MRD/POD-III/CIR/P/2025/134) raises the minimum order size to ₹25 crore, widens the price band to ±3%, and refines the afternoon reference price to the VWAP between 1:45 PM and 2:00 PM. Effective December 2025. This is the framework in force today.

The bulk deal definition, by contrast, has been stable since SEBI circular SEBI/MRD/SE/Cir-7/2004 dated January 14, 2004 — the same 0.5% threshold has held for over two decades.

Why Both Mechanisms Exist

You might be wondering — why does India need two parallel mechanisms for big trades? Wouldn't one be simpler?

The answer is that they solve different problems. A bulk deal isn't actually a different mechanism at all — it's just normal market trading that crosses a size threshold and therefore has to be disclosed. The disclosure is the regulation; the trade itself is identical to any other trade. The point is transparency: if a single client moves 0.5% of a listed company in one day, the rest of the market deserves to know who did it, so that institutional activity can be observed and tracked.

A block deal solves the opposite problem. Sometimes a buyer and seller have already agreed — promoter is exiting, a strategic investor is entering, a mutual fund is offloading a stake to another mutual fund. Forcing them to put that pre-arranged trade through the open market would damage the price for everyone else without any benefit. The block deal window lets them do the trade at a pre-agreed price within a narrow band, and the full details get published afterwards so the market still gets transparency — just not real-time transparency.

Bulk deals are about watching big money in motion. Block deals are about recording deals that were already done.

Both are heavily regulated. Both require disclosure. Both require delivery. The difference is only in when and how the market sees the trade.

What This Means for a Retail Investor

Here's where most beginner articles go wrong. They explain the mechanics, then jump to "so track these deals to find the next multi-bagger!" as if institutional activity were a coded signal.

It isn't. And I'll tell you why from my own experience.

Over the years, I've watched dozens of bulk deal headlines play out. Big fund buys 1% of a smallcap — the stock goes up 5% the next day on the news, then sells off over the next two weeks because the buyer was wrong. Promoter sells 2% of a midcap — everyone panics, the stock falls 8%, and three months later it's back to where it was because the sale was just personal financial planning, not a negative view.

Large investors are not always right. They are sometimes hedging a derivatives position you can't see. They are sometimes exiting one stake to free capital for a completely different one. They are sometimes responding to a redemption request they didn't want to fulfill. And occasionally, yes, they have a genuine view on the company — but you have no way to know which scenario you're looking at from the deal data alone.

The right way to use bulk and block deal data is as one input among many. If a respected long-term institutional buyer adds to a stock in a sector you already like, that's a useful confirmation. If multiple FIIs are buying a stock that has clean fundamentals, a reasonable valuation, and a setup you understand technically — yes, that's stronger than any one of those signals alone. But the deal data is the cherry on top, not the cake.

Where to Find Today's Deals

The official sources are the cleanest. NSE publishes bulk deals and block deals separately on its website under the Reports section every trading day, usually by 6 PM. BSE does the same. Both list the stock, the client, the quantity, and the price.

The catch with the official lists: they're flat data, no filters, no historical view, no fundamental context. You'll see "Mutual Fund X bought 50 lakh shares of Stock Y at ₹247.30" — and that's it. You don't see what sector Stock Y is in, whether the buyer has been accumulating for weeks, or whether the fundamentals are improving.

For research-grade analysis, you'll want a tool that joins the deal data with company fundamentals, technicals, and history. Aggregators like Moneycontrol, Trendlyne, and Screener.in cover this — and so does VRD Nation's Screener, with the bulk- and block-deal scan I mentioned earlier.