Anchor Investors in IPO: Lock-in Rules and Expiry Impact

Anchor investors are large institutions, such as mutual funds, insurers and foreign funds, that buy part of an IPO one working day before it opens to the public. As of October 2026, half of their shares are locked in for 30 days from allotment and the other half for 90 days. When each lock-in ends, those shares become free to sell, which is why traders watch the expiry dates.

This guide explains how the anchor book works, what the lock-in means for you as a retail investor, and how to use the anchor disclosure without over-reading it. To see which issues are open or listing soon, check our live IPO dashboard.

What the anchor portion is

The QIB (qualified institutional buyer) portion of a mainboard book-built IPO can allocate up to 60% of itself to anchor investors. The rules sit in SEBI's ICDR Regulations, 2018 (Schedule XIII). Key points as of October 2026:

• Who bids: QIBs only. Promoters, the lead managers and their related parties cannot be anchors, apart from limited exceptions for certain funds sponsored by lead managers.
• When: one working day before the issue opens (the "anchor bidding day").
• Minimum size: each anchor applies for a large amount (the regulations set a crore-level minimum per anchor).
• Reservation for domestic institutions: SEBI's amendment notified in late 2025 raised the reserved slice of the anchor book to 40%, generally reported as one-third for domestic mutual funds and the rest for insurers and pension funds, with any unsubscribed insurer/pension part going to mutual funds.
• Price: anchors are allotted at the anchor price. If the final issue price is higher, anchors pay the difference; if lower, they get no refund.

How the lock-in works

The lock-in runs from the date of allotment in the IPO, not the anchor bidding day or the listing day.

• Tranche 1 (50%): locked for 30 days.
• Tranche 2 (50%): locked for 90 days.

Before April 2022, all anchor shares were locked for only 30 days. SEBI added the 90-day tranche so that anchors could not exit soon after listing gains, which had worried regulators.

Anchors are not the only ones with a lock-in. Under the ICDR Regulations, the promoters' minimum contribution (20% of the post-issue capital) is locked for 18 months, promoter holding above that for 6 months, and most pre-IPO shareholders for 6 months from allotment. These dates are in the RHP's "Capital Structure" section. For the pre-IPO side, see pre-IPO and unlisted shares risks.

Worked example: lock-in dates and supply (illustrative)

An IPO of 5 crore shares closes on 3 March. Allotment happens on 5 March and listing on 6 March. Anchors receive 1.5 crore shares.

Suppose the company has 20 crore shares in total after the IPO, but on listing only the 5 crore IPO shares minus the locked anchor shares trade freely: 5 crore − 1.5 crore = 3.5 crore.

• On 4 April, free float rises from 3.5 crore to 4.25 crore shares, an increase of 0.75 ÷ 3.5 = about 21%.
• On 3 June, it rises to 5 crore, a further 0.75 ÷ 4.25 = about 18%.

That jump in sellable supply is why expiry dates matter. Whether anyone actually sells is a different question. The exact dates come from the company's exchange filings, so use those rather than your own count, since the end date can shift depending on how the period is reckoned.

What happens around lock-in expiry

Prices can move for a few reasons:

• Profit-taking. If the stock has risen sharply from the issue price, some anchors may book gains.
• Rebalancing. Funds with fixed position limits may trim.
• Anticipation. Traders sometimes sell before the date, so any fall may come early, or not at all.
• Holding. Long-only funds that like the business often keep or add, which can steady the price.

Studies and market reports over recent years show mixed results: some stocks dip around expiry, many do not move much, and some rise. Treat expiry as one input, not a signal. Because anchors are allotted discretionarily, the presence of well-known names does not guarantee a good listing either.

How to read the anchor disclosure

1. Find the anchor allocation filing on NSE or BSE, released the evening before the issue opens.
2. Check who the anchors are. A long-only mix (domestic mutual funds, insurers, pension funds) is generally read as steadier than a book of short-horizon funds.
3. Check the size. Compare the anchor amount with the total QIB portion.
4. Note the lock-in end dates in your calendar app if you hold the stock.
5. Read the RHP for valuation, use of proceeds and risks; anchors' interest is not a substitute. See how to read the IPO offer document.

What it means for a retail investor

If you were allotted shares in the IPO, the anchor lock-in does not restrict you; you can sell from listing day. It matters in three practical ways:

• If you plan to hold for a few weeks, know the 30-day and 90-day dates so a dip around them does not surprise you.
• If you plan to buy after listing, some investors prefer to wait until after the first expiry, when the extra supply has been absorbed. There is no guarantee this gives a better price.
• If you hold for years, the expiry dates matter little; the company's earnings will drive returns.

You can confirm the dates in the company's lock-in disclosures on the exchange website rather than relying on social media posts.

Common myths

• "Anchors got shares cheaper." They pay at least the final issue price; any discount must be paid up.
• "A full anchor book means guaranteed listing gains." It shows institutional interest at that price, not future returns.
• "All anchors sell on day 30." Many hold well beyond 90 days.
• "Anchor shares affect my retail allotment." The anchor portion comes from the QIB quota, not the retail quota.

Once you hold an IPO stock for a year or more, measure its return properly with our CAGR calculator. For how the QIB, NII and retail quotas are split, see IPO categories: retail, sHNI and bHNI. This article is educational and does not recommend any IPO or stock.

Key takeaways

• Anchor investors are large QIBs that buy up to 60% of the QIB portion one working day before the IPO opens.
• As of October 2026, 50% of anchor shares are locked for 30 days and 50% for 90 days from allotment.
• Lock-in expiry increases sellable supply; prices may or may not react.
• Promoter and pre-IPO shareholder lock-ins are separate and are listed in the RHP.
• Use the anchor list as a signal of interest, not as a reason on its own to apply or hold.