How lot size is set
The lot size is not chosen for elegance. It is worked backwards from a minimum application value the regulator sets, using the upper end of the price band. On the mainboard the minimum application is meant to land between roughly ₹10,000 and ₹15,000, so a company pricing at ₹871 a share ends up with a lot of 17 shares — 17 × 871 is ₹14,807 — while one pricing at ₹97 ends up with a lot of 154.
This is why lot sizes look so arbitrary across issues. They are all solving the same equation with a different price. If you ever want to sanity-check a lot size you have seen quoted somewhere, multiply it by the upper band price: the answer should be just under ₹15,000 for a mainboard issue.
Why SME lots cost seven times more
On the SME boards — NSE Emerge and BSE SME — the minimum application is set near ₹1 lakh rather than ₹15,000. The same arithmetic then produces very different lots: 600 shares at ₹189 is ₹1,13,400, and 1,200 shares at ₹118 is ₹1,41,600.
The gap is deliberate. SME issues are smaller, less researched and far less liquid than mainboard listings, and the higher entry threshold is a filter — it is meant to keep the smallest investors out of the riskiest listings. Whether it works as a filter is arguable, but the practical consequence is not: applying for one SME lot is a six-figure commitment in a stock that may trade very thinly afterwards.
The gap is also large enough to be a useful check. There is no borderline between the two boards — mainboard applications cluster just under ₹15,000 and SME applications sit above ₹1 lakh, with nothing in between. We use exactly that arithmetic internally to catch issues the exchange feeds have filed under the wrong board.
Applying for more than one lot
Retail applicants can apply for multiple lots up to a ceiling — currently ₹2 lakh in application value. Beyond that you are no longer bidding as retail; the application moves into the non-institutional (NII) category, which has its own reservation, its own allotment mechanics and, on the mainboard, its own split between small and big NII.
Applying for more lots does not proportionally improve your odds in an oversubscribed retail category. When retail is oversubscribed, allotment is a lottery run on applications at the one-lot level, not a proportional carve-up. Ten applications of one lot each, made from ten different PANs, is a materially different bet from one application of ten lots — the first is ten entries in the draw, the second is usually one.
Applying more than once from the same PAN is not a way around this. Duplicate applications on a single PAN are rejected, and the rejection takes the whole set with it.
Cut-off price
Retail applicants can tick a box marked “cut-off” instead of naming a price. It means: whatever the issue finally prices at, I will pay it. Since the great majority of decent issues price at the top of the band, this is usually the same as bidding the upper band price — but it protects you from the one scenario that quietly disqualifies people, which is bidding below the final price and having the application rejected for it.
If you bid a specific price below the eventual issue price, you get nothing. Not a smaller allotment — nothing. Cut-off exists so that retail applicants do not lose an allotment on a technicality.
What actually leaves your account
Nothing, at first. Applications go through ASBA, where the money is blocked in your bank account rather than debited: you keep earning interest on it, and it stays yours until shares are actually allotted. Retail applications up to ₹5 lakh usually run through a UPI mandate, which you have to approve in your UPI app before a cut-off time on the closing day. Miss that approval and the application never enters the book.
If you get no allotment, the block is simply released. If you get a partial allotment, only that part is debited. How to check what you were allotted.