Small NII vs big NII

Where sNII and bNII fit

An IPO is split among investor categories: retail, non-institutional (NII) and qualified institutional buyers (QIB). Read IPO investor categories for the full picture.

The NII category is for bids above ₹2 lakh. Since April 2022, it is split into two parts:

If one part does not get enough bids, its unused shares can go to the other. Every mainboard RHP states this in its “Issue Structure” section.

How allotment works in each

Before 2022, NII shares went in proportion to bid size, so the biggest bids took most of the shares. SEBI changed that.

Now, in both sNII and bNII, allotment works in two steps:

1. Minimum application first. Each winner gets the minimum NII application: the smallest number of lots worth more than ₹2 lakh.
2. Draw when needed. If there are more applicants than such blocks, winners are picked by a draw of lots.
3. Balance in proportion. Any shares left after every applicant has a block are shared in proportion to bid size.

So in a popular IPO, a ₹10 lakh bid and a ₹2.1 lakh bid compete for the same prize: one block worth just over ₹2 lakh.

The rules for NII bids

NII bids follow stricter rules than retail bids:

• No cut-off price. You must enter a price. A bid below the final issue price gets nothing.
• No cancelling or lowering. Once placed, an NII bid stays.
• UPI up to ₹5 lakh. Larger bids go through net banking ASBA, which blocks the money the same way.
• Category follows the amount. The app places your bid in sNII or bNII based on its value at your bid price.

A worked example

Take Bombay Coated and Special Steels, which bid in October 2026 with a price band up to ₹82 and a lot of 182 shares. These figures are our calculation at ₹82.

NSE’s final figures showed sNII subscribed 107.91 times and bNII 183.52 times.

Now a rough comparison of chances. Assume every applicant bids the smallest amount in their part.

1. sNII. Each applicant bids exactly one block of 2,548 shares, so there are about 108 applicants per block. That is roughly a 1 in 108 chance.
2. bNII. Each applicant bids 12,376 shares, almost five blocks. At 183.52 times, there are about 38 applicants per block. That is roughly a 1 in 38 chance.

These are our illustrative calculations. Real applicants bid different amounts, which changes the odds. But they show why the subscription figure alone does not give your chance.

Why bNII can be oversubscribed more but still give better odds

The times-subscribed figure counts shares bid, not applicants. In bNII, each applicant bids at least ₹10 lakh, so fewer applicants make up the same demand.

Because each winner gets only one minimum block, fewer applicants per block means a better chance per application. That is why a bNII figure of 180 times can mean better odds than an sNII figure of 108 times.

The trade-off is cash. A bNII bid blocks more than ₹10 lakh until allotment, to win a block worth about ₹2 lakh. The rest is released on T+2.

What 2026 IPOs show

Across 108 mainboard IPOs in 2026 with both figures on NSE, our calculation shows:

• bNII was subscribed more than sNII in 81 of them. sNII was higher in 27.
• The middle values were close: sNII about 25.7 times and bNII about 26.7 times.
• sNII was subscribed more than retail in 90 of 108. The middle retail figure was about 8.1 times.

So in most 2026 IPOs, both NII parts were far more crowded than retail. Retail allotment also works by draw, for one lot. Read chances of getting an IPO allotment to compare.

Reading sNII and bNII during bidding

The exchanges publish subscription by category several times a day while an IPO is open. NII figures behave in a particular way.

• They often jump on the last day. Many large NII bids arrive in the final hours.
• bNII can move sharply. A few very large bids can add many times to the bNII figure in one update.
• The final figure is what counts. The basis of allotment uses the final numbers after the close, not the day-one figures.

So a low NII figure on the first day says little about where it will end. Watch the figure on the closing day, and read the final numbers after 5 pm.

If you are allotted in NII

If your NII bid wins, here is what usually happens:

1. T+1. The registrar’s allotment status shows the number of shares, usually one minimum block.
2. T+2. Your bank debits the amount for those shares and releases the rest of the blocked money.
3. T+2 evening. The shares reach your demat account.
4. T+3. The shares list, and you can sell or hold them like any other.

For a bNII bid of ₹10 lakh that wins one block of about ₹2 lakh, roughly ₹8 lakh is released on T+2. Read how to check IPO allotment status for where to look.

Choosing between retail, sNII and bNII

For most individuals the realistic choice is a retail bid or an sNII bid. Each has a different trade-off:

• Retail needs one lot, about ₹15,000 in a mainboard IPO. It allows cut-off and cancelling until the close.
• sNII needs more than ₹2 lakh blocked, for a chance at one block worth just over ₹2 lakh.
• bNII needs more than ₹10 lakh blocked, for the same prize, usually with better odds per application.

This site does not recommend which to choose. Compare the category figures on each IPO page before deciding.

Common mistakes to avoid

• Reading times subscribed as your odds. Shares bid and applicants are different things.
• Expecting to get your full bid. In a popular issue, NII winners usually get only the minimum block.
• Bidding below the final price. Without cut-off, a low price means no allotment.
• Crossing ₹2 lakh by accident. A bid just over ₹2 lakh becomes an NII bid, which you cannot cancel.
• Forgetting the money is blocked. A bNII bid ties up more than ₹10 lakh until T+2.

What to do next

Read how IPO shares are allotted and IPO subscription status explained. Each IPO page on this site shows sNII and bNII subscription from NSE during bidding; see open IPOs.

Sources: SEBI (Issue of Capital and Disclosure Requirements) Regulations, 2018, as amended in January 2022: NII split into two sub-categories and minimum application allotment; Outcome of SEBI board meeting, 28 Dec 2021 (NII split for issues opening on or after 1 Apr 2022); Bombay Coated and Special Steels RHP, Issue Structure (non-institutional portion and sub-categories), October 2026; NSE issue data for 2026 mainboard IPOs (category-wise subscription), compiled in the IPO24by7 year archive.

Frequently asked questions