What is the difference between book building and fixed price IPO? In a fixed price IPO the company announces one price before the issue opens, while in a book-built IPO investors bid within a price band and the final price is found from demand. Almost everything else follows from that single difference.
How a Fixed Price IPO Works
The simplest method sets the price first and asks the market second.
- The issuer decides the price in consultation with the merchant banker before the IPO opens
- Every applicant pays that same price, and it stays fixed through the offer period
- Demand is known only after the issue closes, so you apply without seeing how others are bidding
- At least 50% of the issue is reserved for retail investors
- It’s faster and cheaper to run than book building, but the price may not reflect true demand, which risks underpricing or overpricing
How a Book-Built IPO Works
Here the company gives a range and lets investors set the price.
- The issuer announces a price band with a floor and a cap
- Under SEBI’s rules, the cap can’t exceed 120% of the floor, so the band spans a 20% range
- Investors bid at a price within the band, or at the cut-off price, which means they accept whatever final price is fixed
- When bidding closes, the final price is set from the demand received
- If the final price is below the cap, applicants who bid at the cap are refunded the difference
Seeing Demand as It Builds
The biggest practical difference for you is what you can watch while the issue is open.
- In a book-built IPO, category-wise subscription data is visible on NSE and BSE during the offer period
- In a fixed price IPO, there’s nothing to watch, since demand becomes known only once the issue closes
- Companies can also revise the price band during a book-built issue. The floor can move up or down by up to 20% of the floor price disclosed in the RHP, and the subscription window must then be extended
- A fixed price can’t change once the issue is open
Who Gets What
The reservations differ because the two methods are built for different audiences.
- Book building: institutions play a large role, with a standard split of 50% for QIBs, 15% for non-institutional investors and 35% for retail
- Fixed price: the focus is retail and smaller investors, with at least 50% reserved for retail and less institutional influence on price
- Institutional bids in a book-built issue help the market arrive at a price that reflects their analysis
Where Each Method Is Used
Usage in India has settled into a clear pattern, though one source says the opposite.
- Most guides say book building is used mainly for mainboard IPOs and fixed price mostly for SME IPOs
- A major 2026 view is that big issues in sectors like technology and finance predominantly use book building
- One guide reverses this, describing fixed price as common for mainboard IPOs and book building as typical for SME ones. That conflicts with the majority view and with how large IPOs actually run, so treat it as the outlier
- A study of Indian IPOs found book building preferred over fixed price
- Dutch auction IPOs exist but are rare in India
Cost and Complexity
The extra visibility of book building comes at a price.
- Book building has higher issue costs, because it involves more steps: building the order book, running a price band and, often, an anchor round
- Fixed price issues are described as faster and simpler, with lower costs
- For retail investors, fixed price is easier to understand, while book building is slightly more complex but more market-driven
The Trade-Offs
Neither method is better in every case.
- Fixed price risk: the price is set without demand data, so it can be too high or too low
- Book building risk: open demand data can also create herd behaviour, where people chase subscription numbers or grey market buzz
- Real-time data helps price discovery, but it doesn’t guarantee a good listing
What It Means for You as an Applicant
A few habits follow from the method you’re dealing with.
- In a book-built IPO, check the price band and decide whether to bid at cut-off, which is what retail applicants commonly do
- Remember that cut-off bids block money at the cap price, and any excess is released if the final price is lower
- In a fixed price IPO, do your valuation work upfront, since you’ll have no demand signal
- Check the offer document to see which method is used and the reservation split
FAQs
Q1. What is the price band in a book-built IPO?
It’s a range with a floor and a cap, within which investors bid. SEBI’s rules say the cap can’t exceed 120% of the floor.
Q2. Do fixed price IPOs show subscription data while open?
Not in a useful way. Demand is known only after the issue closes, whereas book-built issues show live subscription data on NSE and BSE.
Q3. Which method do mainboard IPOs use?
Mostly book building. Fixed price is largely seen in SME IPOs, though one guide says the reverse, which conflicts with the majority view.
Q4. Can the price band change after the IPO opens?
Yes, in a book-built IPO the floor can be revised by up to 20% on either side, and the subscription window must be extended. A fixed price can’t change.
