IPO Lot Size Explained

Try to apply for 37 shares in an Indian IPO and the form will reject you. Public issues are not sold share by share. They are sold in fixed bundles, and the bundle is called the lot, or in exchange language the market lot. The offer document names one number — say 60 shares — and from that point every valid application in the issue is for 60 shares, or 120, or 180, and never for anything in between.

That looks like a small administrative detail. It is not. The lot number decides the smallest amount of money you can put into an offer, it decides how many applications the registrar has to sort through, and in a heavily oversubscribed issue it decides whether allotment is a proportion or a draw of lots. Most of the confusion beginners have about why they got zero shares in one IPO and a full lot in another traces back to this one number.

What a Lot Actually Is

A lot is the indivisible unit of application for a particular offer. It is fixed by the issuer in consultation with the lead managers, disclosed in the red herring prospectus and in the exchange's issue notice, and it does not change during bidding. Two things follow from the definition. First, there is a minimum: you must bid for at least one lot. Second, there is a step: any larger bid must be a whole-number multiple of that lot.

The lot is specific to that IPO. It has no life after listing — once the shares are trading, they can be bought and sold in single units in the cash segment. A reader who has seen lot sizes in the futures and options market should keep the two ideas apart: an F&O lot is a permanent contract specification for a listed underlying, while an IPO lot exists only for the duration of the public issue.

The Reason Applications Are Bundled at All

The most direct reason is that a public issue is a bulk distribution exercise run against a deadline. A mainboard offer can attract lakhs of applications in three days. Every one of them has to be validated, mapped to a PAN and a demat account, checked against a blocked bank balance, put through a category-wise allocation, and then converted into a credit of shares. Allowing arbitrary quantities would multiply the processing burden without adding anything useful.

The deeper reason is a policy one. Regulation sets a range for the value of a minimum application, so that the entry ticket into an IPO is neither trivially small nor unreachable for an ordinary household. A very low entry point would flood the book with token applications that clog the system; a very high one would shut retail investors out of primary issues altogether. The lot is the device through which that policy is expressed in shares rather than in rupees. The exact rupee range has been revised over the years, so treat it as a rule that exists rather than a figure to memorise, and check the current limits with SEBI or the exchange.

“The lot size is not chosen for the investor's convenience. It is the arithmetic bridge between a regulated minimum application value and a share price that the issuer only discovers after bidding closes.”

How the Number Is Arrived At

The lot is derived from the price band, and specifically from its upper end. The issuer works backwards: at the cap price, one lot must produce a rupee value that falls inside the permitted range for a minimum application. Dividing the target application value by the cap price gives a raw number of shares, and that raw number is then rounded to a tidy figure.

1. The price band is settled first, because the lot cannot be computed without a cap price.
2. The permitted minimum application value is divided by the cap price to get an approximate share count.
3. That count is rounded to a convenient round number, which is why lots so often land on figures like 15, 20, 40, 60, 75 or 100.
4. The resulting lot is checked at both ends of the band to confirm the application value stays inside the permitted range.
5. The final figure is disclosed in the offer document and in the exchange bidding system before the issue opens.

This mechanism explains a pattern that puzzles new investors: expensive shares come with small lots and cheap shares with large ones. In an illustrative issue priced at a cap of ₹200, a lot of 60 shares gives an application value of ₹12,000. In another illustrative issue with a cap of ₹1,200, the same target value can only be reached with a lot of about 10 shares. The two lot sizes look wildly different, but the money involved is roughly the same. These numbers are constructed to show the arithmetic and are not drawn from any actual offer.

Because the lot is fixed against the cap, an application priced lower in the band costs slightly less per lot. That difference does not change the lot; it only changes the amount finally debited if the issue prices below the cap, since the balance is unblocked after allotment.

Minimums, Multiples and the Category Ceiling

One lot is the floor. Above it, the applicant chooses a number of lots, and the upper end is not open-ended either. The retail individual investor category is defined by a rupee ceiling on the total application value. Apply for a number of lots whose value stays under that ceiling and you are bidding as a retail investor; cross it and your bid moves into the non-institutional investor category, where the reservation, the allocation rules and even the sub-categories are different. The QIB, NII and retail categories article in this series sets out those differences.

The practical consequence is that each IPO has a maximum number of lots a retail applicant can bid for, and that maximum falls as the cap price rises. In an illustrative offer where one lot costs ₹12,000, a retail ceiling would accommodate a certain number of lots; in an offer where one lot costs ₹15,000, it accommodates fewer. The bidding platform enforces this, and a bid that exceeds the retail ceiling is simply treated as a non-institutional bid rather than rejected. The current ceiling is set by regulation and has been changed in the past, so confirm the figure that applies at the time you are bidding.

• Minimum: one lot. There is no such thing as a half-lot or an odd-lot application in a public issue.
• Step: whole multiples only — one, two, three lots and so on, never a fraction in between.
• Category boundary: total application value, not lot count, decides whether you are retail or non-institutional.
• One PAN, one application: multiple applications under the same PAN in the same category are liable to be rejected, so a family cannot simply file several forms from one person's identity.
• Different family members with their own PAN, demat account and bank account can apply separately, each bid standing on its own.
• The lot size shown on your broker's screen should match the offer document; if it does not, trust the offer document and the exchange notice.

Where Lot Size Meets the Allotment Maths

This is where the lot stops being an administrative rule and starts determining outcomes. Allotment in the retail category is worked out in lots, not in shares, because the registrar cannot credit a partial lot. That constraint forces two very different procedures depending on how much demand the issue attracted.

When Retail Demand Is Within the Available Shares

If the retail portion is subscribed once or less, every valid retail applicant can be given the full number of lots applied for. Nobody has to be turned away, and the arithmetic is straightforward. Where the retail portion is undersubscribed, the unsubscribed shares may in some circumstances be moved to other categories under the rules set out in the offer document.

When Retail Demand Exceeds the Shares Available

Here the indivisibility of the lot bites. Suppose an illustrative retail portion of 30 lakh shares faces bids for 90 lakh shares, all in lots of 60. Dividing proportionally would give each applicant a third of what they asked for, which for a single-lot applicant means 20 shares — an impossible allotment, because the smallest unit that can be credited is one lot of 60. The rules therefore guarantee that each successful retail applicant gets at least one lot, and the number of applicants who can be made successful is capped by the shares available divided by the lot size. When there are more applicants than that number, the successful ones are picked by a computerised draw of lots supervised by the registrar and the designated exchange.

Three consequences follow, and they explain most of the disappointment retail applicants feel after a popular issue. First, in a heavily oversubscribed offer, applying for more lots does not improve your chance of getting the minimum allotment, because the draw operates on applications. Second, in such an issue nobody in the retail category receives more than one lot until every applicant in the draw has been given one. Third, the smaller the lot size relative to the retail portion, the more applicants can be accommodated — a mechanical fact, not a strategy. The basis of allotment and IPO allotment process articles walk through the full procedure, including how the non-institutional categories are treated differently.

Lot Size in SME Issues

Offers on the SME platforms of the exchanges follow the same logic with a different setting. The minimum application value prescribed for SME issues is substantially higher than for mainboard offers, which produces much larger lot sizes in share terms and a much bigger cheque for a single application. The design is deliberate: SME issues are smaller, thinner and more volatile, and the higher entry point is meant to restrict them to investors who can absorb that risk. SME shares also continue to trade in lot multiples after listing, unlike mainboard shares. Our Mainboard vs SME IPO article covers the wider set of differences; the point to carry here is that the phrase 'one lot' means a very different amount of money on the two platforms.

Common Mistakes

• Assuming a bigger application improves the odds of getting something. In an oversubscribed retail category, the draw runs on applications, so a five-lot bid and a one-lot bid have the same chance of the minimum allotment.
• Filing several applications from the same PAN. They are liable to be rejected together, which can leave you with nothing at all.
• Sizing the application on the floor price. The amount blocked is computed on the cap, and an account funded only for the floor risks a failed mandate.
• Treating a small lot size as a sign of a small or safe company. Lot size follows the cap price, not the quality of the business.
• Applying for a number of lots that quietly crosses the retail ceiling and then expecting retail allotment treatment.
• Comparing lot sizes across two IPOs as if they were comparable. Compare application value instead; that is the number that is actually held roughly constant.
• Ignoring that funds must remain blocked and available until allotment, not merely present on the day of application.

Working Out Your Own Numbers

Before applying, do three multiplications on paper. Lot size times cap price gives the amount that will be blocked for one lot. That figure times the number of lots gives your total blocked amount, which must be available in the bank account backing the application. And the retail ceiling divided by the single-lot value tells you the largest number of lots that keeps you inside the retail category.

1. Take the lot size and the cap price from the red herring prospectus or the exchange notice, not from a forwarded message.
2. Compute the value of one lot and confirm it against the figure your broker's application screen displays.
3. Decide the number of lots, keeping the total inside the retail ceiling if you want retail treatment.
4. Ensure the full amount can stay blocked in the account until the allotment is finalised.
5. Apply from one PAN only, with the demat account and bank account belonging to the same person.
6. Size the application against your own finances rather than against how popular the issue appears to be.

The lot size, in the end, is a plumbing decision that the issuer makes for its own operational reasons and that the regulator constrains for policy reasons. It is not a signal about the company, and it carries no information about whether an offer is worth applying to. What it does deserve is five minutes of arithmetic before you press submit — because it determines exactly how much money leaves your control, for how long, and on what terms you might get shares at the end of it.