Non-Institutional Investor (NII) Category in an IPO: Small and Big NII Buckets Explained

Put in more than ₹2 lakh for a mainboard IPO and you stop being a retail applicant. Your bid moves into the non-institutional investor IPO category, the NII bucket, where the rules for allotment are quite different from the retail quota most of us start with. People still call these bidders HNIs. SEBI’s word for them is non-institutional investors, and since 2022 the category itself has been split in two.

This guide walks through who counts as an NII, how much of an issue they get, how the small and big NII sub-buckets work, and what a winning allotment actually looks like, with a worked example. Everything regulatory here comes from SEBI’s ICDR Regulations, 2018 (as amended up to March 21, 2026) and SEBI’s investor FAQ on public issues.

Who is a non-institutional investor in an IPO?

The definition is done by elimination. Regulation 2(1)(jj) of the ICDR Regulations says a non-institutional investor is “an investor other than a retail individual investor and qualified institutional buyer”. So if you are not a QIB (mutual funds, insurers, banks, FPIs and the like) and you don’t fit the retail definition, you are an NII.

For individuals, the line is the application amount. SEBI’s FAQ puts it plainly: the retail individual investor limit stays at up to ₹2 lakh, and applications above ₹2 lakh and up to ₹5 lakh made through UPI are treated as non-institutional. Above ₹5 lakh you are still an NII, you just can’t use UPI to block the money, because SEBI’s FAQ caps UPI applications by individual investors at ₹5 lakh. You apply through ASBA with a Self Certified Syndicate Bank instead.

Because the definition works by elimination, the category isn’t only for individuals. Any bidder that is neither a QIB nor a retail individual lands here, so a company or trust that doesn’t qualify as a QIB competes in the same pool as you.

If you want the retail side of the same picture first, our explainer on the retail individual investor quota covers the 35% rule and lot sizes.

How big is the NII quota?

It depends on which eligibility route the company used to come to market. Regulation 32 of ICDR sets the split for book-built issues:

• Profitability route, Regulation 6(1): not less than 35% of the net offer to retail individual investors, not less than 15% to non-institutional investors, and not more than 50% to QIBs.
• Loss-making or other route, Regulation 6(2): not more than 10% to retail, not more than 15% to non-institutional investors, and not less than 75% to QIBs.

So in a normal profitable-company IPO, NIIs get at least 15% of the net offer. In a 6(2) issue, the kind many new-age companies use, 15% becomes the ceiling instead of the floor. Our piece on IPO eligibility norms under Regulation 6(1) and 6(2) explains which companies fall where.

One proviso helps when demand is lopsided. Regulation 32 allows any unsubscribed part of the retail or NII portion to be allocated to applicants in another category. A weak NII book can pass shares on; a weak retail book can do the same in reverse.

Small NII and big NII: the 2022 split

This split is fairly recent. The footnotes in the regulations show it was inserted by a 2022 ICDR amendment, effective for issues opening on or after April 1, 2022, and from July 1, 2022 for issues of ₹10,000 crore or more. The minimum-allotment rule covered in the next section came in through the same amendment.

Regulation 32(3A) now says that in a book-built issue:

• One-third of the NII portion is reserved for applications of more than ₹2 lakh and up to ₹10 lakh. This is the bucket the market calls small NII, or sNII.
• Two-thirds is reserved for applications of more than ₹10 lakh. This is big NII, or bNII.

If either sub-bucket falls short, its unsubscribed part can be given to applicants in the other sub-bucket.

Once a bucket is oversubscribed, NII allotment stops rewarding the biggest cheque and starts looking like a lottery for a fixed ticket size.

The allotment rule that changes everything

The bigger change is in how shares are handed out. Regulation 49(4A) says the allotment to each non-institutional investor shall not be less than the minimum application size, subject to shares being available in the category. Whatever is left after that is allotted proportionately, as laid out in the schedules.

Read that slowly. Every successful NII gets at least the minimum NII ticket, which is just over ₹2 lakh worth of shares. If there are not enough shares to give everyone that ticket, SEBI’s own illustration in Schedule XIV shows the winners being picked by lottery, and the rest get nothing. It works much like the retail one-lot lottery, only with a ₹2 lakh-plus ticket instead of one lot.

What is the minimum NII application size?

For a mainboard issue, Regulation 47(2) has the company fix a minimum application size worth between ₹10,000 and ₹15,000. That is one lot. The NII minimum is the smallest number of lots whose value is more than ₹2 lakh.

SEBI’s illustration uses a ₹600 share and a 20-share lot. Twenty lots would be 400 shares, or ₹2,40,000, but 17 lots (340 shares) already comes to ₹2,04,000, which is above ₹2 lakh. So the NII minimum there is 340 shares. Sixteen lots would be ₹1,92,000, still retail.

A worked example: one IPO, two outcomes

The numbers below are a hypothetical issue we built for illustration. They are not from any real IPO.

The setup. A profitable company prices its IPO at ₹500 a share with a lot size of 28 shares, so one lot costs ₹14,000. The net offer is 60 lakh shares and the NII portion is the minimum 15%, which is 9 lakh shares. Split under Regulation 32(3A):

• Small NII (₹2 lakh to ₹10 lakh): one-third, or 3,00,000 shares.
• Big NII (above ₹10 lakh): two-thirds, or 6,00,000 shares.

The ticket sizes. At ₹14,000 a lot, 14 lots is ₹1,96,000 and still retail. 15 lots is 420 shares worth ₹2,10,000, so that is the minimum NII application. The largest small NII bid is 71 lots, or 1,988 shares worth ₹9,94,000. One more lot, 72 lots or 2,016 shares worth ₹10,08,000, pushes you into big NII.

Outcome 1: small NII subscribed 1.5 times

Say 400 people apply in small NII and their bids add up to 4,50,000 shares, which is 1.5 times the 3,00,000 on offer.

1. First, everyone gets the minimum ticket: 400 × 420 = 1,68,000 shares.
2. That leaves 3,00,000 − 1,68,000 = 1,32,000 shares.
3. Total demand above the minimum is 4,50,000 − 1,68,000 = 2,82,000 shares.
4. So each applicant gets about 1,32,000 ÷ 2,82,000, or roughly 46.8%, of whatever they bid above 420 shares.

An investor who bid the full 1,988 shares had 1,568 shares above the minimum. Roughly 46.8% of that is about 734 shares, so they end up with around 1,154 shares. Someone who bid 840 shares gets 420 plus about 197, close to 617. The registrar’s final figures depend on rounding in the basis of allotment, but the shape is the same as SEBI’s own Example A, where every applicant gets the minimum first and the rest is shared in proportion to the excess bid.

Outcome 2: small NII subscribed 40 times

Now the hot-IPO case. 20,000 people apply in small NII, bidding a total of 1.2 crore shares, 40 times the 3,00,000 on offer.

The bucket can give the 420-share minimum to at most 3,00,000 ÷ 420 = 714 applicants (rounded down). So 714 people get 420 shares each and 19,286 get nothing. The odds work out to about 3.6% per application.

Here’s the part people miss: the person who bid ₹9.94 lakh has no better shot than the person who bid ₹2.1 lakh. SEBI’s Example B spreads the lottery winners across each application-size group in proportion to how many people applied at that size, and every winner gets exactly the minimum. Bidding bigger inside small NII buys you nothing in an oversubscribed issue except more money blocked.

And big NII?

The same minimum-ticket rule applies. With 6,00,000 shares, big NII can hand 420-share tickets to at most 1,428 winners. Suppose 3,000 applicants bid 25 times the bucket, about 1.5 crore shares. Giving each the minimum would need 12,60,000 shares, more than the bucket holds, so a draw decides it, and about 1,428 of 3,000 applications win, close to 48%.

Those odds look far better than small NII, and in our example they are. The catch is the price of entry: each of those applications had to block more than ₹10 lakh, and a winner still walks away with only ₹2.1 lakh of stock. Real-world odds depend entirely on how many applications each bucket gets, which you only see in the exchange’s category-wise data. Our explainer on IPO basis of allotment shows how to read the final basis document once it is out.

In a heavily oversubscribed issue, a ₹9.94 lakh small NII bid and a ₹2.1 lakh one hold the same lottery ticket.

Rules NIIs often get wrong

You can’t back out. Schedule XIII of ICDR says QIBs and non-institutional investors are not permitted to withdraw or lower the size of their bids at any stage of the issue. Once the money is blocked, it stays blocked until the basis of allotment is done.

The cut-off option is a retail feature. The same schedule says retail individual investors may bid at the “cut off” price. NII bids are placed at a specific price, and only bids at or above the final issue price are considered for allotment. If the price band is revised upwards, or you bid at the bottom of the band, check that your bid still qualifies.

There is a ceiling on bid size. Under Regulation 47(1), a non-institutional investor’s application cannot exceed the total shares offered in the issue minus the shares offered to QIBs.

The money is blocked, not debited. SEBI’s FAQ notes that ASBA is mandatory for retail, NII and QIB applicants in public issues, so the amount sits blocked in your account and is unblocked if you don’t get an allotment. The funds are still tied up, and if you borrowed to bid, the interest clock is running.

Should you bid in small NII or big NII?

There is no single answer, and anyone who gives you one is guessing at subscription numbers that don’t exist yet. A few practical points, though.

• If you bid small NII, bid the minimum. In an oversubscribed bucket everyone wins the same ticket, so the extra lots only tie up cash. In an undersubscribed bucket you get what you bid, so think about how much you actually want to own.
• Compare odds, not subscription multiples. A 25x big NII book can give better odds than a 10x small NII book, because big NII has twice the shares and far fewer applicants per crore. Work out shares available ÷ minimum ticket, then divide by the number of applications, when the data is published.
• Price the capital. If you are borrowing for a big NII bid, the interest for the blocked days comes straight off your listing gain, and a winning allotment is only about ₹2 lakh worth of stock.
• Know what you’re buying. A lottery ticket is still an investment in a company. Read the red herring prospectus before you bid, just as you would at retail size.

For the full sequence from DRHP to listing day, the IPO investing in India guide pulls our IPO explainers together in one place.

Quick recap of the numbers

• NII means any bidder who is neither a QIB nor a retail individual investor; for individuals, that means applications above ₹2 lakh.
• NIIs get not less than 15% of the net offer in a Regulation 6(1) book-built issue and not more than 15% in a 6(2) issue.
• One-third of the NII portion is for ₹2 lakh to ₹10 lakh applications, two-thirds for above ₹10 lakh.
• Each successful NII gets at least the minimum NII application size; in a heavily oversubscribed bucket that means a draw.
• NIIs cannot withdraw or lower bids, and UPI only works up to ₹5 lakh.

Disclaimer: This article is for education only and is not investment advice or a recommendation to apply for any IPO. The worked example uses hypothetical numbers. Rules can change, so check the current SEBI regulations and the offer document of any issue before you bid, and consult a SEBI-registered adviser if you need personal advice.