IPO Lock-In Period: Promoter and Anchor Lock-Ups Explained

An IPO lists on a Tuesday, the stock pops 40%, and a first-time investor asks the obvious question: if everyone made money, why can the founders not sell their shares too? The answer is the IPO lock-in period — a set of rules that freezes big shareholders in place for months after listing, even while you are free to trade. Understanding the IPO lock-in period tells you who is stuck, for how long, and why a calendar date months after listing can quietly move the price. This guide walks through the promoter, pre-issue and anchor-investor lock-ins under SEBI's ICDR regulations, in plain language, with no live-issue calls.

What is an IPO lock-in period?

An IPO lock-in period is a window after listing during which specified shareholders cannot sell their shares. It applies to the people who owned the company before it went public — promoters, early investors, employees holding stock — and to the anchor investors who were allotted shares a day before the issue opened. Retail investors who applied in the public issue are never locked in; you can sell your allotment on listing day if you choose.

The purpose is stability. If every pre-IPO shareholder could dump stock the moment it listed, supply would swamp a newly listed company and the price would swing violently. Lock-ins stagger that supply. They also signal commitment: a promoter who stays invested for a year and a half after listing has their own capital riding on the company's performance.

These rules are not optional or negotiated deal by deal. They are written into the SEBI (Issue of Capital and Disclosure Requirements) Regulations, 2018 — usually shortened to the ICDR regulations — and every mainboard IPO in India follows the same framework. Lock-in periods sit at the far end of the listing journey; if you want the full sequence from draft prospectus to listing day, our explainer on the IPO process in India maps every stage. If you want to build this knowledge properly rather than piece it together issue by issue, a structured stock market training course covers the primary market end to end.

Promoter lock-in: the 18-month minimum contribution rule

Promoters carry the heaviest lock-in, and for good reason — they control the company. SEBI splits their holding into two buckets with two different clocks.

First, the minimum promoter contribution (MPC). Promoters must together hold at least 20% of the post-issue capital, and that 20% is locked in for 18 months from the date of allotment under Regulation 16 of the ICDR regulations. This is the core commitment stake: the slice of the company the founders are required to keep skin in.

Second, any promoter holding above that 20%. Promoters usually own far more than the minimum, and the excess is locked for a shorter six months from allotment. So a founder group holding, say, 55% before the issue keeps 20% frozen for a year and a half and the balance frozen for six months.

There is one important exception. Where the majority of the fresh-issue proceeds are earmarked for capital expenditure — building a plant, buying equipment — the clocks lengthen: the minimum contribution is locked for three years and the excess holding for one year. The logic is that a capex-heavy company takes longer to show results, so promoters should stay committed longer. Note that only eligible shares count toward the 20%; pledged shares and certain shares acquired without a cash cost generally do not qualify.

Pre-issue and other shareholder lock-ins

Promoters are not the only ones who held shares before the IPO. Private-equity funds, angel investors, early employees and other pre-issue shareholders also own stock that was never offered to the public. SEBI locks this pre-issue non-promoter capital for six months from allotment under Regulation 17.

There are sensible carve-outs. Shares held by eligible institutional investors such as certain alternative investment funds and foreign venture capital investors, and some employee shares issued under approved stock-option plans, can be exempt from this six-month freeze or treated differently. The detail varies, which is exactly why the lock-in schedule for a specific company is spelled out in its offer document rather than assumed.

A quick word on SME IPOs, which list on the dedicated small and medium enterprise platforms. These follow a stricter regime: the minimum promoter contribution is ordinarily locked for three years, and a 2025 amendment staggered the excess promoter holding so that half is locked for two years and half for one year. If you are reading a small-company issue, do not assume the mainboard 18-month number applies.

One more distinction worth holding onto: lock-in is about who can sell and when, not about where the money came from. If you want to understand whether the shares on offer are newly created or simply changing hands, that is a separate question covered in fresh issue versus offer for sale.

Anchor investor lock-in: the 30 and 90-day split

Anchor investors are large institutional buyers — qualified institutional buyers bidding at least ₹10 crore — who are allotted shares one day before the public issue opens. Their presence signals confidence to retail applicants. We cover who they are and what their bidding tells you in detail in our guide to anchor investors in an IPO; here the focus is purely their lock-in.

Anchor shares carry a split lock-in. Half of an anchor investor's allocation is locked for 30 days from allotment, and the remaining half is locked for 90 days from allotment. Both clocks start at allotment, not listing, so the first tranche frees up roughly a month after the stock begins trading and the second tranche about three months in.

This two-stage design is deliberate. It means anchor supply does not hit the market all at once, softening the impact of any selling when the lock-in ends. For a retail investor watching a recently listed stock, the 30-day and 90-day marks are dates worth knowing, because they are the moments when a fresh block of shares can legally come up for sale.

Before and after 2021: how SEBI shortened the clock

The current numbers are more relaxed than they used to be. In August 2021, SEBI notified an amendment to the ICDR regulations that materially cut promoter lock-ins, and the anchor rule was tightened separately from April 2022. Taken together, the framework was redesigned to balance two goals: keep promoters committed, but let legitimate pre-IPO capital exit sooner, and stop anchors from exiting in a single rush.

Why did the anchor rule move the other way — tighter, not looser? Market data had shown heavy selling pressure as the old uniform 30-day anchor lock-in expired. One analysis of issues in 2021 found selling pressure around the 30-day mark on the large majority of IPOs it studied. Splitting the lock-in into two tranches spread that supply out and was intended to reduce the price volatility that followed listings.

Why IPO lock-in expiry can move the share price

This is the practical payoff of understanding lock-ins. A lock-in expiry does not force anyone to sell, but it allows a large, previously frozen block of shares to be sold for the first time. When that supply becomes available, basic supply and demand can weigh on the price, especially if early investors are sitting on large gains and want to book them.

The effect is strongest when three things line up: a big block unlocking at once, early shareholders holding deep paper profits, and thin everyday trading volume in the stock. A lightly traded recent listing can struggle to absorb a wave of selling when a pre-issue investor's six-month lock-in ends, or when the anchor 90-day tranche frees up.

That said, an expiry is a known, scheduled event, not a surprise. The dates are derivable from the allotment date disclosed in the offer document. Experienced investors treat them as something to be aware of, not something to trade on blindly — plenty of stocks sail through a lock-in expiry with no drama because the holders simply choose to stay invested. The point is awareness, not prediction: knowing a block can unlock helps you read a price move that would otherwise look mysterious.

What this means for you as an IPO applicant

You will never be locked in as a retail applicant, so why does this matter to you? Because the lock-in schedule is one of the cleanest windows into how aligned a company's insiders are. A promoter group keeping its minimum contribution frozen for 18 months — or three years on a capex-heavy issue — has its own money committed to the outcome you are buying into.

Three habits make lock-ins useful rather than academic. First, read the "capital structure" and lock-in section of the offer document so you know which blocks unlock when. Second, mark the key dates — the six-month pre-issue expiry, the anchor 30-day and 90-day tranches, the 18-month promoter date. Third, treat an approaching expiry as context for a price move, never as a guaranteed signal to buy or sell. Lock-ins are a reading skill, and reading the primary market well is something you can learn systematically rather than by trial and error on your own capital.

Frequently Asked Questions

What is the IPO lock-in period for promoters in India?

The minimum promoter contribution — at least 20% of post-issue capital — is locked in for 18 months from the date of allotment under SEBI's ICDR regulations. Any promoter holding above that 20% is locked in for six months. If the majority of fresh-issue proceeds fund capital expenditure, these periods extend to three years and one year respectively.

How long is the anchor investor lock-in period?

Anchor investor shares have a split lock-in. Half of the allocation is locked for 30 days from allotment and the remaining half for 90 days from allotment. This two-stage rule applies to issues that opened on or after 1 April 2022; before that, the entire anchor allocation was locked for just 30 days.

Are retail investors locked in after an IPO?

No. Retail investors who receive an allotment in the public issue are free to sell their shares from listing day onwards. The IPO lock-in period applies only to promoters, other pre-issue shareholders and anchor investors — the people who held or were allotted shares before the issue opened to the public.

Does the lock-in period start from allotment or from listing?

Under the ICDR regulations the lock-in is counted from the date of allotment, which is a few days before listing. Some popular explainers loosely say "from listing", but the regulation uses allotment as the reference point. For exact expiry dates on a specific company, the allotment date and lock-in schedule are disclosed in its red herring prospectus.

Why does a share price sometimes fall when the lock-in period ends?

A lock-in expiry releases a block of previously frozen shares that can now be sold. If early investors want to book profits, that extra supply can pressure the price, particularly in a thinly traded stock. It is not automatic — many holders stay invested — but it explains why some recently listed stocks dip around a lock-in expiry date.

Disclaimer: This article is for educational purposes only and does not constitute investment advice. Markets carry risk — please do your own research or consult a qualified financial professional before investing. NIFM provides training and exam preparation; certification exams conducted by regulatory or professional bodies are administered by those bodies independently.