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Guide· 8 min read

sNII (₹2L–₹10L) vs bNII (₹10L+): Category Bidding Mathematics & HNI Funding Cost Math

SEBI split the HNI IPO category into sNII and bNII with separate quotas and allotment rules. Complete mathematical guide to allotment probabilities, application sizing, and NBFC borrowing cost calculations.

ED
IPOSathi ResearchPrimary Market Desk

Published on · Verified Analysis

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Editorial Key Takeaways

This analysis is based on official Draft Red Herring Prospectus (DRED) filings, historical peer valuation multiples, and exchange data. Figures are audited for institutional accuracy.

In This Article

  1. 1.1. Category Breakdown & Quota Reservations
  2. 2.2. Allotment Mechanics: The Minimum Lot Rule
  3. 3.3. Mathematical Optimization: How Much Should You Bid?
  4. 4.4. HNI Borrowing & Funding Cost Math
  5. 5.5. Summary Strategy for Investors

In 2022, SEBI restructured the Non-Institutional Investor (NII / HNI) category into two separate sub-categories: Small NII (sNII) and Big NII (bNII).

This guide breaks down the mathematics of allotment, application sizing, and funding cost dynamics.

1. Category Breakdown & Quota Reservations

In a standard mainboard IPO with a 15% overall NII allocation:

CategoryApplication RangeShare of NII QuotaEffective Share of Net IssueMode of Application
**Small NII (sNII)**₹2,00,000 to ₹10,00,000**33.33% (1/3rd)**5.0% of Total IPOUPI (up to ₹5L) or Net Banking ASBA
**Big NII (bNII)**Above ₹10,00,000**66.67% (2/3rds)**10.0% of Total IPONet Banking ASBA only

2. Allotment Mechanics: The Minimum Lot Rule

The Old System (Before 2022): HNIs who applied for ₹100 Crore received massive proportionate allocations, completely crowding out middle-class investors.

The Current System (Post-2022):

1. sNII Allotment: In oversubscribed issues, allocation is done through a computerized draw of lots. Winners receive exactly 1 Minimum NII Lot (worth just above ₹2,00,000).

2. bNII Allotment: Winners in the bNII lottery receive a baseline allotment of 1 Minimum NII Lot; any remaining shares are distributed proportionately among winners.

3. Mathematical Optimization: How Much Should You Bid?

In sNII:

  • Optimal Bid: Bid for the exact minimum number of shares that cross ₹2,00,000 (e.g. ₹2,08,000).
  • Why? Bidding ₹8,00,000 in sNII gives you the exact same lottery probability as someone bidding ₹2,08,000 because all successful applicants are awarded only 1 minimum lot. Bidding extra capital simply locks up liquidity with zero improvement in odds.

    • In bNII:

  • Optimal Bid: Bid for the exact minimum number of shares that cross ₹10,00,000 (e.g. ₹10,15,000).

    • 4. HNI Borrowing & Funding Cost Math

    Many HNIs apply for bNII using short-term financing from NBFCs (e.g., JM Financial, Edelweiss) at 9–11% annualized interest for 4–5 days.

    $$ ext{Borrowing Cost per Share} = rac{ ext{Bid Amount} imes ext{Interest Rate} imes ext{Days}}{365 imes ext{Allotted Shares}}$$

    When an issue is 100x subscribed in bNII, the interest cost can easily exceed ₹120–₹180 per share. If the listing gain (GMP) is less than the funding cost, leveraged HNIs incur net cash losses even with a positive listing!

    5. Summary Strategy for Investors

    1. If Issue is Heavily Oversubscribed (>30x): Split family capital into multiple ₹2 Lakh sNII applications across different PANs to maximize lottery draw entries.

    2. Self-Funded vs Leveraged: Always prefer self-funded ASBA over NBFC funding to eliminate interest drag.

    *Disclaimer: Educational analysis only. Consult a SEBI-registered financial advisor.*

    ED

    About IPOSathi Research

    Primary Market Analyst & Senior Financial Journalist · IPO Latest Updates Daily

    Our research desk specializes in reading SEBI Red Herring Prospectuses, institutional anchor allocations, and forensic balance sheet audits. Every report follows rigorous E-E-A-T research standards without promoter sponsorship.