IPO GMP, Lot Size, Subscription & Allotment Explained (2026)

IPO GMP (Grey Market Premium) is the extra price, over and above an IPO’s issue price, that buyers in an unofficial “grey market” are willing to pay for shares before they list on the stock exchange — so a GMP of ₹100 on a ₹500 issue hints at a possible listing near ₹600. But GMP is an informal, unregulated rumour-based number, not a guarantee. This guide explains GMP honestly, then walks you through the four things that actually decide your outcome in an Indian IPO: lot size and minimum investment, subscription and oversubscription, the allotment basis (and your real odds), and listing gains.

What is IPO GMP (grey market premium)?

When a company launches an Initial Public Offering (IPO), it sets a price band and you apply for shares during the 3-day subscription window. The shares only start trading on the NSE/BSE on the listing day, which is typically a few working days after the issue closes. In that gap, an informal, off-the-record market — the “grey market” — springs up where dealers buy and sell IPO applications and allotment rights before listing.

The Grey Market Premium (GMP) is simply the premium being quoted in that grey market. If an IPO’s issue price is ₹500 and the GMP is ₹100, it means grey-market participants are (informally) willing to pay ₹600 per share — implying the market expects the stock to list around ₹600, a roughly 20% listing gain. A negative GMP means the grey market expects the stock to list below its issue price.

The two grey-market terms you’ll hear

• GMP (Grey Market Premium): the per-share premium over the issue price, e.g. “GMP ₹100”.
• Kostak & “Subject to Sauda”: a Kostak is a fixed amount a dealer pays to buy your full IPO application outright (whether or not you get allotment). “Subject to Sauda” is a deal that only settles if you actually receive an allotment. These are dealer-to-dealer arrangements with no legal protection.

Why GMP is unofficial — and risky to trust

This is the part most “IPO GMP today” websites won’t tell you plainly. The grey market is informal and unregulated. It is not run, recognised, or endorsed by SEBI, the NSE, the BSE, or any merchant banker. The numbers you see floating across Telegram channels and IPO-tracking sites are typically based on a handful of dealer quotes and rumour, and they can be exaggerated, stale, or even deliberately manipulated to influence sentiment.

Five honest limitations of GMP

• No official source. There is no exchange or regulator publishing GMP. Different sites quote different numbers for the same IPO on the same day.
• It can be manipulated. Because it is rumour-driven, interested parties can talk the GMP up or down.
• It is volatile. GMP can swing sharply in the final hours before listing as sentiment changes.
• It ignores fundamentals. GMP says nothing about the company’s profits, debt, valuation, or business quality.
• It is not actionable for most retail investors. You cannot reliably or legally “cash in” the GMP — it is a number, not a market you can easily transact in.

Instead of chasing GMP, read the company’s Red Herring Prospectus (RHP), check who the promoters and anchor investors are, study the valuation versus listed peers, and understand what the company will do with the money. Those signals are official and far more reliable than a grey-market whisper.

Lot size & minimum investment

You cannot apply for a single share in an IPO. SEBI requires applications in fixed bundles called lots. The lot size is the number of shares in one lot, and you must apply in multiples of it (1 lot, 2 lots, 3 lots, and so on).

SEBI’s rule of thumb is that one lot should cost roughly ₹14,000 to ₹15,000 at the upper end of the price band — this keeps the minimum retail application affordable. So the company divides that target by the cap price to arrive at the lot size.

How lot size is calculated (worked example)

Illustrative figures to show the maths — always confirm the exact lot size in the IPO’s RHP and on your broker’s app.

Investor categories and how much you can apply for

Indian IPOs split the offer into reserved buckets. The category you fall into decides your minimum and maximum bid:

*Reservations differ for loss-making companies (where QIBs get a larger share). The Non-Institutional Investor (NII) bucket is now split into S-HNI and B-HNI, each allotted by a lottery rather than purely pro-rata, to give smaller HNIs a fairer chance.

Subscription & oversubscription explained

“Subscription” tells you how much demand an IPO is attracting versus the shares on offer. It is shown as a multiple, e.g. “the IPO was subscribed 12x.”

• Subscribed 1x: applications exactly match the shares on offer.
• Undersubscribed (< 1x): fewer applications than shares offered. If the issue can’t reach 90% subscription, it can be withdrawn and money refunded.
• Oversubscribed (> 1x): more demand than supply — the most common outcome for popular IPOs. The higher the oversubscription, the lower your chance of allotment.

Why oversubscription matters to you

Each category (Retail, NII, QIB) is subscribed separately. If the retail portion is oversubscribed 10x, it means there are 10 times as many retail applicants as available retail shares — so roughly only 1 in 10 retail applicants will get an allotment. This is the single biggest driver of your odds.

Allotment basis & your real odds

“Allotment” is the process of deciding who actually receives shares when demand exceeds supply. SEBI mandates a fair, transparent allotment method for retail investors, and it is intentionally designed so that small and large retail applicants are treated equally at the lot level.

The key SEBI rule: minimum one lot to maximum applicants

When the retail category is oversubscribed, shares are not handed out in proportion to how many lots you applied for. Instead, the registrar tries to give at least one lot to as many applicants as possible. If there aren’t enough shares even for that, a computerised lottery (draw of lots) decides who gets the single lot — and everyone else gets a full refund.

How retail allotment works, step by step

Practical ways to (slightly) improve your odds

• Apply with multiple distinct PANs/demat accounts in your family (e.g. self, spouse, parents) — each is treated as a separate applicant in the lottery. Never apply more than once with the same PAN; duplicate applications get rejected.
• Apply for one lot, not many, in a heavily oversubscribed retail issue — it maximises the number of “chances” your money can buy across family accounts.
• Bid at the cut-off price so your application isn’t rejected for under-bidding.
• Avoid last-minute glitches — apply a day early so UPI mandate approval doesn’t fail at the deadline.

How to check your allotment status

After the basis of allotment is finalised (usually a day or two after the issue closes), you can check status on: the registrar’s website (e.g. KFin Technologies or Link Intime/MUFG Intime), the BSE IPO allotment page, or directly in your broker app. You’ll need your PAN, application number, or demat (DP) ID.

Listing gains: GMP vs reality

A listing gain is the profit (or loss) on listing day, measured from the issue price to the price at which the stock opens or closes. If you got shares at ₹500 and the stock opens at ₹600, that’s a 20% listing gain.

This is exactly where GMP tries to predict the outcome — and where it frequently misses. GMP is a pre-listing rumour; the actual opening price is set by genuine buy/sell orders during the special pre-open session on listing day.

A sensible IPO checklist

Before you apply to any IPO, run through this quick list rather than reacting to GMP headlines:

• Read the RHP basics: what the company does, its revenue and profit trend, and its debt.
• Check the “objects of the issue”: is the money funding growth, or just letting existing investors exit (Offer for Sale)?
• Compare valuation: is the P/E reasonable versus listed peers?
• Look at anchor & QIB demand: strong institutional interest is a more credible signal than GMP.
• Confirm lot size and your budget: only invest money you can afford to block for a week or so.
• Decide your plan: listing-day exit or long-term hold — before you apply.

Frequently asked questions

Disclaimer: This article is for educational purposes only and is not investment/financial advice. Read all scheme/offer documents and consult a SEBI-registered adviser where relevant.