Hyundai India’s IPO in October 2024 was one of the biggest in Indian stock market history at ₹27,870 crore. The retail category closed at roughly 0.5x subscription. Not even half the shares set aside for retail investors were applied for. If you had seen only the ₹27,870 crore headline, you would have walked in expecting a packed room. The actual retail pool told a completely different story.

Before your next IPO application, two numbers matter more than anything else: the net issue size and the retail quota. This article walks you through both, including how to calculate them yourself before you apply.

What is the total issue size in an IPO?

Every company that goes public sells shares to raise money. The total issue size is simply the full value of shares being sold, calculated as:

Total Issue Size = Number of Shares Offered × IPO Price

That total is made up of one or both of the following:

Fresh Issue — The company prints new shares and sells them. The money raised goes straight into the company’s books for purposes like paying off debt, funding expansion, or meeting working capital needs.
Offer for Sale (OFS) — Existing shareholders sell shares they already hold. The money goes to those sellers, not to the company. An OFS does not add a single rupee to the company’s finances.

Some IPOs are purely a fresh issue. Some are purely an OFS. Most are a combination of the two. Together, they form the gross or total issue size.

What Is Net Issue Size?

Net issue size is the amount actually open for public bidding. Before any investor applies, certain blocks of shares are carved out from the total.

Employee Reservation Portion — A fixed number of shares set aside for the company’s own employees, typically offered at a discount to the IPO price.
Shareholder Reservation — Some IPOs, particularly where a listed parent or group company exists, reserve shares for shareholders of that parent entity. They get a separate application window entirely.

Once both these portions are removed from the total issue size, what remains is the net issue to the public. This is the number every quota calculation is based on. Not the gross total. Not the headline figure. The net.

Net Issue Size = Total Issue Size − Employee Reservation − Shareholder Reservation

Example:

Total Issue Size: ₹1,000 crore
Employee Reservation: ₹40 crore
Shareholder Reservation: ₹60 crore
Net Issue Size: ₹900 crore

All retail, HNI, and QIB calculations run on ₹900 crore. Using ₹1,000 crore for your allotment math gives you an inflated, wrong number.

How SEBI Splits the Net Issue

SEBI’s ICDR Regulations specify exactly how every mainboard IPO must divide the net issue:

Investor Category	Minimum Allocation	Who Qualifies
Qualified Institutional Buyers (QIB)	50% of net issue	Mutual funds, banks, FIIs, AIFs, insurance companies
Non-Institutional Investors (NII or HNI)	15% of net issue	Individuals applying for more than ₹2 lakh
Retail Individual Investors (RII)	35% of net issue	Individuals applying for up to ₹2 lakh

Within the QIB bucket, up to 60% can go to anchor investors, institutions that subscribe one day before the IPO opens. One-third of the anchor portion is reserved for domestic mutual funds specifically. Since anchors come out of the QIB portion, they do not touch the retail or HNI share at all.

The 2025 SEBI Proposal Every IPO Investor Should Know About

In July 2025, SEBI floated a proposal to reduce the retail quota for large IPOs in a graded structure. For issues above ₹5,000 crore, the retail allocation would have dropped to as low as 10% on the tranche exceeding that threshold, bringing the effective retail quota for mega IPOs down to around 25%.

The reasoning was straightforward: SEBI wanted more institutional participation in large listings to improve price discovery.

The reaction from retail investor groups, analysts, and market participants was swift and largely opposed. In August 2025, SEBI formally dropped the proposal. The 35% retail floor stays in place for all mainboard IPOs, regardless of how large the issue is.

For anyone regularly applying to big-ticket IPOs, this matters. The confirmed 35% floor means the proportional access retail investors have always had is not going anywhere, at least for now.

How to Calculate the Retail Quota

Step 1: Pull up the total issue size from the Red Herring Prospectus or any IPO tracking platform.

Step 2: Subtract the employee reservation and shareholder reservation (if any) to get the net issue size.

Step 3: Multiply the net issue size by 35% to get the retail quota in rupee terms.

Step 4: Divide the retail quota by the upper price band to get the total number of retail shares.

Step 5: Divide the total retail shares by the lot size to find how many retail lots are up for allotment.

Retail Quota (₹) = Net Issue Size × 35%

Retail Shares = Retail Quota ÷ Upper Price Band

Available Retail Lots = Retail Shares ÷ Lot Size

Full Worked Example

Given:

Total Issue Size: ₹1,200 crore
Employee Reservation: ₹30 crore
Shareholder Reservation: ₹20 crore
Upper Price Band: ₹500 per share
Lot Size: 30 shares

Step 1: Net Issue Size
₹1,200 crore − ₹30 crore − ₹20 crore = ₹1,150 crore

Step 2: Retail Quota
₹1,150 crore × 35% = ₹402.5 crore

Step 3: Total Retail Shares
₹4,02,50,00,000 ÷ ₹500 = 80,50,000 shares

Step 4: Available Retail Lots
80,50,000 ÷ 30 = 2,68,333 lots

This IPO can allot shares to a maximum of 2,68,333 retail applicants. If 5 lakh people apply, roughly 1 in 2 gets an allotment. If 40 lakh people apply, the odds fall to about 1 in 15. The winner is picked by computerised lottery.

Running this calculation takes about two minutes and gives you far more useful information than any subscription commentary published after the fact.

Mainboard IPO vs SME IPO Allocation Rules

A common assumption among beginners is that all IPOs follow the same allocation structure. They do not.

Feature	Mainboard IPO	SME IPO
Retail Quota	35% of net issue	35%, but no separate NII category
NII or HNI Category	15% of net issue	Merged into the broader non-institutional pool
QIB Minimum	50% of net issue	15% of net issue
Anchor Investors	Mandatory above a certain size	Not mandatory
Minimum Application Value	1 lot within ₹2 lakh	Typically ₹1 lakh or more per lot

SME IPOs pool the HNI and retail categories together in many cases, which changes allotment dynamics in ways that are not obvious unless you read the offer document. Do not assume SME rules match mainboard rules.

What Oversubscription Numbers Actually Tell You

When you see “retail subscribed 40x” on your broker app, it means investors applied for 40 times the shares available in the retail quota.

Using the worked example above:

Available retail lots: 2,68,333
At 40x subscription: roughly 1.07 crore applications received
Allotment odds: approximately 1 in 40 applicants

Applying for more lots does not improve these odds. Once the retail category crosses 1x subscription, SEBI’s allotment system gives each applicant one entry in the lottery regardless of how many lots they applied for. A 13-lot application and a 1-lot application get the same draw.

The one scenario where the lot quantity matters is below 1x subscription. If the retail category closes undersubscribed, allotment is proportional to the number of lots applied, and applicants can receive their full requested quantity.

By the second day of the bidding window, live subscription data is available on the BSE and NSE portals. Checking this before you apply on day three gives you a realistic picture of your actual odds.

What Works in Your Favour as a Retail Investor

The 35% floor is protected. No company or underwriter can push retail allocation below this threshold, no matter how much institutional demand exists.
You do not have to predict the price. Selecting a cut-off price on your application means you agree to pay whatever price is finally decided within the band. You do not need to guess where the book closes.
Your money is not debited upfront. Under the ASBA and UPI mandate, your application amount is blocked in your savings account, not debited. It earns interest right up to the point of allotment or refund.
Knowing the retail lot count helps you compare IPOs. A ₹100 crore retail quota in a low-profile IPO with 50,000 applicants can be a better odds bet than a ₹5,000 crore retail quota in a nationally marketed listing with 80 lakh applicants.

Risks to Factor In Before You Apply

Capital is locked for up to 6 working days. From the time you apply until a refund or allotment is credited, your blocked funds cannot be used for trading or other investments. In a volatile market, this is a real cost.
The lottery outcome is blind to effort. You cannot improve your allotment odds through research quality, application timing, or lot quantity in an oversubscribed retail category. The process is intentionally indifferent to all of that.
Large retail quotas still get overwhelmed. A ₹9,000 crore retail quota sounds like more than enough for everyone. When 2 crore applicants show up, the odds per person are still around 1 in 45. Absolute quota size means nothing in isolation.
SME IPO exit risk is real. Post-listing volumes in SME IPOs are often thin. Getting an allotment is the easy part. Selling at a price you are happy with can take considerably longer, depending on market interest in that specific counter.
Grey market premiums have no regulatory standing. GMP figures circulate heavily before every popular IPO. They reflect informal market sentiment, not actual price discovery, and they have been wrong in both directions often enough to treat them with serious scepticism.

Mistakes That Cost Beginners Money and Time

Calculating odds using the gross issue size

Subtracting the reserved portions first is not optional. In an IPO with a ₹500 crore employee reservation inside a ₹10,000 crore gross issue, your retail pool estimate is off by more than 19% if you skip this step.

Applying for maximum lots to boost allotment probability

This is probably the single most widespread misconception in retail IPO participation. Once oversubscribed, the lottery treats a 1 lot application identically to a 13 lot application. The only thing you get from 13 lots is more blocked capital.

Missing the employee or shareholder reservation window

If you work for the company going public, or hold shares of its listed parent group company, you may be eligible for a reserved category with meaningfully better odds. These categories often go partially undersubscribed simply because fewer people know they qualify.

Skipping live subscription data before the close

Day two subscription figures are public. Checking them on BSE or NSE before you decide whether to apply takes five minutes and is the single most practical thing you can do to make a better-informed application decision.

Treating all IPOs as book-built mainboard issues

Fixed price IPOs exist. SME IPOs have different rules. Book-built and fixed-price allotment processes are not the same. Reading the one-page issue summary before you apply costs very little time and prevents avoidable confusion.

Conclusion

In any IPO where retail interest is high, allotment comes down to a lottery. Understanding the net issue size does not change that reality, but it gives you the only number that actually affects your odds: how many lots are available relative to how many people are likely to apply.

A ₹400 crore retail quota with 2 lakh applicants is a far better probability bet than a ₹9,000 crore retail quota with 2 crore applicants. The media covers the bigger number. The five-step calculation tells you the real story. Run it before every application, and you will stop making decisions based on noise.