How Grey Market Premium Works in Indian IPOs

Most investors know the GMP number. Very few know the market that produces it. Understanding the plumbing behind grey market premium makes you far better at judging when the number is meaningful and when it is noise.

The Grey Market Is a Forward Market

Before an IPO lists, its shares legally cannot change hands. The grey market gets around this by trading promises rather than shares. Two parties agree today on a price for something that will exist in a week, and they settle in cash or in shares once listing happens. In market terms it is an informal, unregulated forward market with no clearing house standing between buyer and seller.

That single fact explains almost everything about GMP behaviour: no margining, no exchange guarantee, no audit trail, and pricing driven entirely by the reputation and appetite of a small dealer network.

The Three Instruments You Will Hear About

1. Premium (GMP). The buyer agrees to pay issue price plus a premium for allotted shares. If the issue price is 250 and the premium is 70, the buyer pays 320 per share after listing, whatever the market price turns out to be. The seller has locked a gain; the buyer has taken the listing-day risk.

2. Kostak rate. A flat amount paid for an entire application, decided before allotment. If the Kostak rate is 900 rupees, the applicant receives 900 regardless of whether the application is allotted. This is pure risk transfer: the applicant sells the uncertainty of the allotment lottery.

3. Subject to Sauda. A conditional deal. The buyer pays the agreed amount only if the application receives an allotment. Rates are higher than Kostak because the buyer's payment is contingent.

Retail investors mostly encounter only the first of these, because the GMP is what trackers publish, but Kostak and Sauda rates are useful sentiment signals in their own right. A firm Kostak rate on a heavily oversubscribed issue is a sign that dealers genuinely expect a strong listing.

How a Premium Gets Quoted

A typical price discovery loop looks like this:

• Anchor allotment is announced a day before the issue opens. Dealers read the anchor list and start quoting an opening premium.
• Day one subscription numbers arrive by evening. Retail and HNI take-up moves the quote.
• Institutional bidding on the last day is the biggest single input. QIB books usually fill in the final hours, and premiums often make their sharpest move then.
• Between close and listing, the premium tracks the broader market. A weak Nifty week can halve a premium even after a 60x subscription.

Because each dealer quotes independently, published GMP is a survey. IPOMint aggregates multiple sources and reports a median so a single outlier quote cannot distort the picture. That is also the honest answer to the frequent question of why two websites show 82 and 95 for the same issue on the same day.

Why Premiums Differ So Much Between Issues

• Free float. Small issues with a thin post-listing float support wider premiums, both because supply is scarce and because the premium is easier to influence.
• Issue structure. A pure offer for sale, where no money reaches the company, generally attracts a lower premium than a fresh issue funding expansion or debt reduction.
• Sector cycle. Defence, capital goods, renewable energy and specialty chemicals have all gone through phases when any issue in the sector carried an outsized premium.
• Valuation headroom. When an issue is priced at a discount to listed peers, dealers can justify a premium arithmetically. When it is priced above peers, they cannot.

Compare these variables side by side using the IPO comparison tool.

Settlement, Default and Why That Matters to You

Grey market contracts are settled on trust between dealers who transact repeatedly. When listing goes badly and losses are large, defaults happen and quotes disappear. This is why premiums are least reliable exactly when you most want them to be reliable, in a falling market.

As a retail applicant, you are not a party to any of this. You are simply reading the residue of other people's positions. Never plan your finances around a premium you saw during the bidding window, and never borrow to apply on the basis of a quoted GMP.

Turning GMP Into a Decision

A workable framework:

• Compute the premium as a percentage of the upper band. Below 5 percent, listing gains are likely to be eaten by volatility and taxes.
• Look at premium stability over the bidding window rather than the peak.
• Sanity-check against the subscription book. A rich premium with a weak QIB book is a warning, not an invitation. Check the live subscription status.
• Fold in fundamentals from the prospectus, and use the listing gain calculator to size the realistic rupee outcome per lot.
• Track what actually happened after listing on the IPO performance page so your next estimate is better informed.

For the legal position on all of this, read IPO grey market: legal or illegal. For the difference between the premium and the issue price itself, see difference between IPO price and GMP.

Frequently Asked Questions

Q: Who decides the grey market premium?

A: No single authority. A network of informal dealers quotes two-way prices, and published GMP is a survey median of those quotes.

Q: What is the difference between Kostak and Subject to Sauda?

A: Kostak pays a fixed amount for an application whether or not shares are allotted. Subject to Sauda pays only if the application is allotted, so its rate is higher.

Q: Can retail investors trade in the grey market?

A: Practically, no. Deals run through dealer relationships, are unenforceable and carry counterparty risk. Retail investors should treat GMP as information, not as a market to participate in.

Q: Why does GMP fall just before listing?

A: Because positions are unwound and the broader market takes over as the main driver. A weak index week compresses premiums even for well-subscribed issues.

Q: Does GMP affect the allotment price?

A: No. Allotment is always at the price discovered in the book building process, not at issue price plus premium.