How to Read a Basis of Allotment Document (And Why It Is the Only Honest Source)
By IPO Cracker Editorial Team · 03 Aug 2026
After an IPO closes, the registrar publishes a basis of allotment. Most investors never open it. It is the single most informative document in the whole process, because it is the only place that reports what actually happened rather than what was expected.
What it contains that nothing else does
Subscription figures tell you how many times a category was bid for. The basis of allotment tells you how many applications were received and how many were allotted, category by category. That lets you compute real allotment odds by division, rather than estimating them from a multiple.
It also states the allotment ratio, the number of shares allotted per bidder, and how any surplus was distributed.
How to read it, line by line
- Find your category. Retail, S-HNI, B-HNI, QIB and Employee are reported separately. Odds differ enormously between them.
- Note applications received. This is the true denominator, not the subscription multiple.
- Note the number of allottees. Divide it by applications received and you have the real allotment rate for that category.
- Check shares allotted per bidder. In an oversubscribed issue this is usually the minimum lot, which confirms allotment went by draw of lots rather than proportionately.
- Compare against the estimate you used. This is where most calculators are exposed.
A worked example
From one published document, comparing the common formula against what actually occurred:
| Category | Applications | Allottees | Actual odds | Formula said |
|---|---|---|---|---|
| Retail | 10,60,040 | 1,73,540 | 16.37% | 14.39% |
| S-HNI | 63,450 | 1,769 | 2.79% | 2.74% |
| B-HNI | 36,882 | 3,538 | 9.59% | 1.99% |
| QIB | 101 | 101 | 100% | not applicable |
Three things stand out. Retail did slightly better than the formula predicted. B-HNI did almost five times better. And every single QIB applicant was allotted, because QIB allotment is proportionate rather than a lottery.
Why B-HNI diverges so far
A B-HNI must bid above Rs 10 lakh but is allotted the same minimum NII lot as an S-HNI, because SEBI requires allotment to each NII to be not less than the minimum bid lot. Money enters at Rs 10 lakh and leaves at Rs 2 lakh, so the pool serves roughly five times more allottees than dividing by the subscription multiple suggests.
Where to find it
The registrar publishes it on their own website once allotment is finalised, usually as a PDF alongside the allotment status checker. Under SEBI T+3 timelines, allotment is finalised within about three working days of the issue closing and the shares list on the third working day.
What it cannot tell you
It is published after the fact, so it cannot help you decide whether to apply. Its value is calibration: read a few and you learn how far the estimates you relied on were from reality, which makes you a better reader of the next issue.
It also covers one issue only. Correction factors drift with lot value, so a factor measured on one IPO is a guide rather than a constant.
We use published allotment documents to calibrate our allotment chances calculator. Method: how we calculate allotment odds. To check a result, use IPO allotment status.