Estimate your total shares, total investment, the implied listing price and the listing-day gain for any IPO — from the lot size, issue price, number of lots and the GMP. GMP is an unofficial grey-market estimate, not an official price and not advice.
What GMP is — and why it is speculative
Grey Market Premium (GMP) is the unofficial price at which IPO shares — or the application rights to them — change hands in the grey market before the stock lists on the exchange. If a share is priced at ₹100 and its GMP is ₹20, dealers expect it to open near ₹120 on listing day. It is a real-time gauge of demand, but it is set by a small, unregulated network of dealers with no settlement guarantee, so it is neither an official price nor a promise.
Because there is no exchange behind it, GMP can be noisy and even manipulated. It moves on rumour and subscription buzz, often spiking on the last day of the issue and then collapsing — or surging — at listing. Plenty of IPOs with a healthy GMP have listed flat or at a discount, and a few with a modest GMP have popped. Use it as one sentiment input, never as a forecast.
How the listing gain is estimated
The maths here is deliberately simple and transparent:
- Total shares = lot size × number of lots.
- Total investment = total shares × issue price.
- Estimated listing price = issue price + GMP.
- Estimated listing gain = GMP × total shares (and as a percentage, GMP ÷ issue price).
So a 50-share lot at ₹100 with a GMP of ₹20, applied for 2 lots, is 100 shares costing ₹10,000, an implied listing price of ₹120, and an estimated listing gain of ₹2,000 — about 20.0%, if it lists exactly at the GMP (it may not).
Lot size and application mechanics
A lot is the minimum number of shares you can bid for in one application, fixed by the company so that one retail lot stays near ₹14,000–₹15,000 for mainboard IPOs (SME IPOs use far larger lots). When you apply, your money is not debited — it is blocked via a UPI mandate or ASBA. After the issue closes, the registrar finalises the basis of allotment; if the retail portion is oversubscribed the lots are allotted by a computerised lottery, so you may get fewer lots than you applied for, or none. This calculator assumes full allotment, which is the best case, not the typical one.
Why actual listing prices differ from GMP
The single most important caveat: the price the stock actually opens at on listing day is set by live demand and supply on the exchange, not by the grey market. GMP is only a sentiment snapshot from the days before, and it can be stale or wrong by the time the bell rings. Broader market moves, the final subscription figures, anchor-investor behaviour and overall risk appetite all push the real listing price away from the GMP — sometimes well above it, often below. Treat every number on this page as an estimate, size your application to your own risk, and base the decision on the company's fundamentals and its RHP rather than on the premium.
Frequently Asked Questions
What is GMP (Grey Market Premium)?
GMP is the extra price IPO shares — or the right to receive them — are unofficially changing hands at in the grey market before they list on the exchange. A GMP of ₹20 on a ₹100 share suggests the market expects it to open near ₹120 on listing day. It is an informal demand signal set by a small network of dealers, with no regulator and no settlement guarantee behind it — not an official price and not a recommendation.
How is the estimated listing gain calculated?
The calculator does simple arithmetic: total shares = lot size × number of lots, total investment = shares × issue price, estimated listing price = issue price + GMP, and estimated listing gain = GMP × shares. The percentage is the GMP as a share of the issue price. It assumes the stock lists exactly at issue price + GMP, which is just a what-if — it is not a forecast.
Is GMP a reliable predictor of the actual listing price?
Only loosely. GMP reflects sentiment in the days before listing and can swing sharply right up to listing day. Many IPOs list far from their last GMP, and some list at a discount despite a positive premium. Because there is no official exchange behind it, GMP can be noisy and even manipulated. Treat it as one sentiment input alongside the company's fundamentals, valuation and subscription numbers — never as a guaranteed outcome.
What does "lot size" mean and how many lots can I apply for?
A lot is the minimum number of shares you can apply for in one application. If the lot size is 50 shares at ₹100, one lot costs ₹5,000. Retail investors can apply for up to ₹2,00,000 worth (multiple lots within that cap); apply for more and you move into the HNI/NII category. The number of lots field above lets you model any number of lots you intend to apply for.
Can the listing gain be negative?
Yes. If the GMP is zero, the estimated listing price equals the issue price and the gain is nil. If you enter a negative GMP (a grey-market discount), the calculator shows an estimated listing loss — the stock is expected to open below its issue price. Real listings do this regularly: a positive GMP is no guarantee of a profit, and capital loss is a genuine risk in any IPO.
Does this calculator account for allotment, taxes or charges?
No. It assumes you are allotted every lot you apply for and ignores brokerage, STT, exchange and other charges, as well as any tax on listing gains (short-term capital gains rules apply to shares sold soon after listing). Oversubscribed IPOs are allotted by lottery, so you may receive fewer lots — or none. Use the figure as a clean, before-costs what-if, not a net take-home number.
GMP (Grey Market Premium) is an unofficial, speculative indicator set by grey-market dealers — it is not the official listing price, not a forecast and not investment advice. Listing gains shown here are estimates only and assume full allotment with no charges or tax. Many IPOs list below their GMP; IPO investing carries a real risk of capital loss. Invest based on the company's fundamentals and its RHP, and consult a SEBI-registered adviser before applying.