Key Takeaways

A mainboard IPO typically takes 8-12 months end-to-end; an SME IPO takes 4-6 months.
The IPO process has four major phases: Preparation, Filing & Review, Marketing & Subscription, and Allotment & Listing.
SEBI has mandated T+3 listing (3 working days from issue close to listing) effective from December 2023.
Anchor investor allocation happens one day before the IPO opens to retail investors.
The book building period for mainboard IPOs is 3-5 working days; for SME IPOs, it is 3-4 working days.

The Four Phases of an IPO

Phase 1: Preparation (D-180 to D-60)

This is the longest and most critical phase, covered in detail in Chapter 3.

| Day | Milestone | |---|---| | D-180 | Board meeting to approve IPO; engage merchant banker | | D-170 | Appoint intermediaries — registrar, legal counsel, qualified CAs | | D-150 | Begin Ind AS restatement of financial statements | | D-130 | Corporate governance restructuring — independent directors, committees | | D-120 | ICFR documentation and testing cycle begins | | D-100 | Legal due diligence and title verification | | D-90 | Industry report commissioned (CRISIL/Frost & Sullivan) | | D-75 | DRHP drafting begins — business description, risk factors, objects | | D-60 | Restated financials certified by CAs; board approves DRHP |

Phase 2: Filing & SEBI Review (D-60 to D-15)

| Day | Milestone | |---|---| | D-60 | DRHP filed with SEBI (mainboard) or Stock Exchange (SME) | | D-60 to D-39 | 21-day public comment period | | D-30 | SEBI issues first observations / queries | | D-25 | Issuer responds to SEBI observations | | D-15 | Final SEBI observation letter received |

Phase 3: Marketing & Subscription (D-14 to D-Day)

| Day | Milestone | |---|---| | D-14 | Red Herring Prospectus (RHP) filed with ROC; price band decided | | D-12 to D-7 | Pre-deal roadshows — institutional investor meetings | | D-5 | Statutory advertisement in newspapers | | D-2 | Anchor investor allocation (1 day before issue opens) | | D-Day (Day 1) | IPO opens for subscription | | D-Day + 2 | IPO closes (3 working days for mainboard) |

Phase 4: Allotment & Listing (D-Day + 3 to D-Day + 6)

Under SEBI's T+3 framework (effective December 2023):

| Day | Milestone | |---|---| | T+1 | Basis of allotment finalised by registrar | | T+2 | Refunds initiated for unsuccessful applicants; shares credited to demat accounts | | T+3 | Listing Day — shares begin trading on BSE/NSE |

Landmark Reference: Tata Technologies IPO (November 2023)

The Tata Technologies IPO was among the first major IPOs to list under SEBI's new T+3 timeline. The IPO closed on November 24, 2023, and shares were listed on November 30 — exactly T+3 working days (accounting for a weekend). The issue was subscribed 69.43 times overall, with the retail category oversubscribed 18.6 times. The stock listed at Rs 1,200 against an issue price of Rs 500, delivering a 140% listing gain. This IPO demonstrated that the compressed T+3 timeline does not hinder investor enthusiasm when fundamentals are strong.

Worked Example: Complete Timeline for a Mainboard IPO

Company: XYZ Pharma Ltd | Target Listing: March 2026

| Date | Activity | |---|---| | Sep 2025 | Board approves IPO; merchant banker appointed | | Oct 2025 | Intermediaries engaged; restatement begins | | Nov 2025 | Governance restructuring; independent directors join | | Dec 2025 | DRHP drafting commences; due diligence in progress | | Jan 15, 2026 | Restated financials certified; DRHP approved by board | | Jan 20, 2026 | DRHP filed with SEBI | | Feb 10, 2026 | Public comment period ends | | Feb 20, 2026 | SEBI issues observations | | Feb 28, 2026 | Observations addressed; final letter received | | Mar 5, 2026 | RHP filed with ROC; price band Rs 280-300 per share | | Mar 8-12, 2026 | Institutional roadshows | | Mar 14, 2026 | Anchor investor allocation | | Mar 15, 2026 | IPO opens | | Mar 17, 2026 | IPO closes | | Mar 18, 2026 | Basis of allotment | | Mar 19, 2026 | Refunds and demat credit | | Mar 20, 2026 | Listing Day |

Expert Tip: The biggest bottleneck in the IPO timeline is always the SEBI observation phase. Companies that file a clean, complete DRHP receive observations faster and with fewer queries. Our CAs have observed that companies investing properly in pre-IPO preparation (Chapter 3) typically save 4-6 weeks in the SEBI review phase.

Critical Deadlines & Compliance Windows

| Requirement | Timeline | |---|---| | SEBI observation validity | 12 months from issuance | | IPO must open within | 12 months of SEBI observation letter | | Minimum subscription | 90% of net offer (excluding anchor) | | Refund of subscription money | Within T+2 days of issue close | | Allotment in demat | Within T+2 days of issue close | | Listing | T+3 working days from issue close | | Anchor lock-in (50%) | 90 days | | Anchor lock-in (remaining 50%) | 30 days |

What Can Go Wrong?

Common timeline derailers include:

Incomplete restated financials — Delayed CA certification pushes everything back by months.
SEBI queries on related-party transactions — Multiple rounds of clarification can add 4-8 weeks.
Market volatility — Companies may choose to delay the issue window if markets crash during the subscription period.
Litigation developments — New material litigation during the review period requires DRHP amendment.
Regulatory changes — Mid-process SEBI amendments may require document revisions.

Section Interconnect

Previous: Chapter 5 — DRHP Explained
Next: Chapter 7 — Listing Day: What to Expect
Related: Chapter 3 — Pre-IPO Preparation
Related: Chapter 4 — SEBI ICDR Regulations

Frequently Asked Questions

Can an IPO be postponed after the DRHP is filed?

Yes. Companies can withdraw their DRHP at any stage before the IPO opens. However, if the company wishes to refile later, it must submit a fresh DRHP with updated financials. There is no penalty for withdrawal, but it may raise market concerns about the company's readiness.

What is the anchor investor mechanism?

Anchor investors are QIBs (qualified institutional buyers) who are allocated shares one day before the IPO opens to public subscription. They apply at or above the anchor investor allocation price. Up to 60% of the QIB portion can be allocated to anchor investors. This mechanism provides price support and signals institutional confidence.

How is the allotment done if an IPO is oversubscribed?

For the retail category, if oversubscribed, allotment is done via lottery — each applicant has an equal chance of receiving one lot. For HNI and QIB categories, allotment is proportional to the bid amount. The registrar to the issue conducts the allotment process under exchange supervision.

Disclaimer: This article is for educational and informational purposes only. It does not constitute financial, legal, or investment advice. IPO timelines and SEBI processes are subject to change. Always consult qualified professionals for your specific requirements.

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IPO Process Timeline: Step-by-Step from D-180 to Listing Day