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IPO Lockup Expirations: What the S-1 Tells You

Chad Hartman

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An IPO lockup expiration date is public information months before it arrives, disclosed in plain language in the company's own S-1. Academic research has repeatedly found that the stock still reacts when the date finally comes — measurably, on average, even though nobody involved could claim to be surprised.

Our S-1 guide covers the lockup as one of five things worth checking in a fresh IPO filing. This guide goes deeper into the mechanic itself: exactly where the agreement is disclosed, how long it actually runs, the extension and early-release provisions that change the date after the fact, and what the research says happens to the stock when the restriction finally lifts.

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Table of Contents

What a Lockup Agreement Actually Is

A lockup agreement is not an SEC rule. It is a private contract between the company's underwriters and its pre-IPO shareholders — founders, executives, directors, and often venture and private equity investors — restricting them from selling, or even agreeing to sell, their shares for a set period after the offering. The restriction exists because underwriters don't want the stock they just priced and sold to the public immediately facing a wave of insider selling before a real trading market has formed.

That contractual nature matters for how the restriction can change. Because no regulator wrote the rule, no regulator has to approve a change to it. The underwriters who negotiated the agreement are also the ones who can waive it, extend it, or release it early — and they do all three, on terms the S-1 discloses up front.

Where to Find It in the S-1

The lockup terms appear in two sections of every S-1: Shares Eligible for Future Sale, and Underwriting. The first states the duration and mechanics in the context of how many total shares become freely tradable and when. The second contains the full lockup agreement language, including any early-release discretion the underwriters have reserved for themselves. The Shares Eligible for Future Sale section is usually the faster read — it states the expiration trigger directly, in a sentence structured almost identically across nearly every S-1: shares become eligible for sale some number of days "after the date of this prospectus" or "after the effective date of the registration statement."

That distinction matters. The clock does not start on the day the company files its S-1. It starts on the day the offering actually prices and the final prospectus (Form 424B4) is filed, which can be weeks or months after the initial S-1 hits EDGAR. An investor calculating an expiration date from the S-1 filing date rather than the final pricing date will get the wrong day, sometimes by a significant margin.

How Long a Lockup Typically Runs

180 days is the standard duration in the U.S. market, though 90-day lockups appear as well, and the two aren't mutually exclusive within the same offering. A meaningful share of S-1 filings disclose a tiered structure: a portion of shares becomes eligible at 90 days, a second tranche at a middle point such as 135 days, and the remainder at the full 180-day mark. Reading the actual share counts tied to each tranche — not just the headline "180 days" figure most coverage repeats — tells you how much of the float is actually locked at each stage. A 180-day lockup where 90% of restricted shares release at day 90 behaves nothing like one where 90% waits for the full term.

The structures that show up across S-1 filings, and what can move each one:

Structure Typical length What starts the clock What can move the date
Standard single-tranche lockup 180 days Date of the final prospectus (Form 424B4), not the S-1 filing date Automatic extension trigger; underwriter early release
Shorter single-tranche lockup 90 days Date of the final prospectus (Form 424B4), not the S-1 filing date Automatic extension trigger; underwriter early release
Tiered lockup Staged — a portion at 90 days, a tranche at a middle point such as 135 days, the remainder at 180 days Date of the final prospectus (Form 424B4), not the S-1 filing date Automatic extension trigger; underwriter early release
Rule 144 / Rule 701 eligibility — (set by rule, not by contract) — Independent of the lockup agreement; in nearly every S-1 this eligibility arrives before the lockup lifts

Rule 144 and Rule 701 add another layer underneath the contractual lockup. Both rules independently govern when restricted and compensatory shares become legally eligible for public resale, and in nearly every S-1 that eligibility arrives before the lockup does — meaning the lockup agreement, not federal securities law, is usually the binding constraint on when insiders can actually sell.

The Automatic Extension Trigger

Many lockup agreements contain a provision that most retail coverage never mentions. If the company issues an earnings release, or discloses material news, within a defined window before the lockup's scheduled expiration — commonly the last 15 to 17 days of the lockup period — the expiration date automatically extends. The new date typically lands roughly three business days after that earnings release or disclosure. The purpose is narrow: prevent insiders from being freed to sell into the exact window when the market is digesting fresh material information they may have had advance knowledge of.

The practical effect is that a lockup's calculated expiration date is provisional, not fixed, for any company whose earnings calendar happens to land near it. A lockup nominally set to expire 180 days after pricing can, and often does, extend automatically if the company's next quarterly release falls inside that trailing window — which is common, since many companies report quarterly roughly every 90 days.

Early Release: When Underwriters Waive the Lockup

Underwriters retain discretion to release some or all locked-up shares before the scheduled date, and the S-1's Underwriting section states plainly whether they've reserved that discretion — nearly all do, while stating they have no current intention of using it. An early release for officers and directors specifically triggers a disclosure requirement. FINRA rules require the underwriter to announce the release publicly, by press release, and the waiver cannot take effect until at least two business days after that announcement.

That two-day announcement window exists because early releases for a small group of insiders — often to fund a specific liquidity need — are themselves market-moving information, and the rule gives the broader market notice before the shares can actually trade. A press release announcing an early lockup release for named executives, distributed ahead of the original expiration date, is worth reading closely: it names exactly who is being released and how many shares, which the S-1's original terms never could.

The 2025 IPO class made the point repeatedly. Three of its largest listings all carried a nominal 180-day lockup, and in all three the date that mattered was not the one 180 days out:

Company Nominal lockup What actually moved the date
CoreWeave 180 days from the March 2025 prospectus An earnings trigger terminated it early. The lockup lifted on August 14, 2025, two trading days after the Q2 2025 earnings release on August 12 — roughly six weeks ahead of the calendar date
Circle 180 days from the June 5, 2025 prospectus, expiring December 2, 2025 An early-release provision freed roughly 11.5 million shares around August 13, 2025, more than three months before the headline date
Figma 180 days, with an extended agreement layered on top A price condition was met after the close on September 4, 2025, releasing 25% of eligible employee and service-provider securities at the open on September 5. Holders of roughly 54.1% of Class A shares had separately signed extended lockups with staggered quarterly releases running through June 2026

Read down that column and the pattern is that the headline expiration date was the least useful number in each agreement. Two of the three were pulled forward by a trigger written into the original contract, and the third had a second, longer agreement sitting behind the one the prospectus described. None of that is visible from the 180-day figure alone.

What Happens to the Stock When a Lockup Expires

Field and Hanka's 1,948-agreement study, published in the Journal of Finance in 2001, remains the foundational academic work on this question. It found a permanent 40% increase in average trading volume once lockups expired, alongside a statistically significant three-day abnormal return of -1.5% around the expiration date. The pattern reads as insiders finally selling into a market that hadn't yet priced in the coming increase in tradable float. The effect was substantially larger for venture-capital-backed companies than for non-VC-backed ones, consistent with VC funds facing their own pressure to return capital to their limited partners rather than hold indefinitely.

The 2025 cohort offers an unusually clean read on this, because in all three cases the lockup came off at an earnings filing rather than on the calendar date. CoreWeave's Q2 10-Q was filed August 13, 2025 and the lockup terminated the next day. Circle's Q2 10-Q was filed August 12 and its early-release tranche freed shares the day after. Figma's Q2 10-Q was filed September 3 and its price-condition release came at the open on September 5. Measuring forward from each of those filing dates:

Company Filing that released the lockup 1 month 2 months 3 months
CoreWeave Q2 2025 10-Q, filed Aug 13, 2025 -24.35% +14.46% +13.54%
Circle Q2 2025 10-Q, filed Aug 12, 2025 -29.81% -10.68% -22.20%
Figma Q2 2025 10-Q, filed Sep 3, 2025 -22.34% -21.68% -49.64%

All three fell between 22% and 30% in the month that followed. Two of the three were still down at three months; CoreWeave recovered and finished the window higher. Three companies is not a base rate, and the filing date is not identical to the release date — it precedes it by one to two days in each case, and an earnings release moves a stock on its own merits regardless of what a lockup does. But it is worth noting how much larger these moves are than the -1.5% three-day average the academic literature describes, and that all three point the same direction.

Later studies across different markets and time periods have consistently found the same directional pattern — a volume spike and a modest average negative return — even though the expiration date is public information known months in advance. That persistence is itself the interesting part: a fully efficient market should have priced the coming supply increase in before it happened. The fact that researchers keep finding a measurable reaction anyway suggests the date matters more to how the market actually behaves than pure efficiency theory would predict. None of this is a guarantee for any individual stock — averages describe a tendency across many companies, not a forecast for one — but it's the reason lockup expiration dates draw disproportionate attention from short sellers and options traders in the weeks beforehand.

How to Track a Lockup Expiration Date

Tracking a specific company's lockup expiration takes three steps, and the second one is the part investors most often get wrong.

Step 1: Find the Lockup Section in the S-1 or 424B4

Search the company's final prospectus (Form 424B4) rather than the original S-1 for the exact day count. Pull up "Shares Eligible for Future Sale" for the headline terms and "Underwriting" for the full agreement language, including any early-release discretion. This is a filing-text lookup rather than a financial-data lookup — how GeminIQ compares to BamSEC covers where reading filing language ends and working with as-filed financial data begins.

Step 2: Calculate the Expiration Date

Anchor the day count to the prospectus date, not the S-1 filing date. A "180 days after the date of this prospectus" clause means 180 days from when the offering actually priced — typically the same day the 424B4 is filed — not 180 days from whenever the company first filed its S-1 months earlier.

Step 3: Watch for Form 4 Filings Around the Date

Once the calculated date approaches, watch the company's Form 4 filing activity directly. A cluster of S-coded sales landing right at or after the expiration date confirms insiders are exercising the freedom the lockup just released; an early press release announcing a waiver for named executives is a signal the actual date has moved up.

Tracking the Aftermath on GeminIQ

The lockup agreement itself is contractual language in the S-1, not XBRL-tagged financial data, so it isn't something GeminIQ extracts directly. What GeminIQ tracks is everything that happens once the lockup does its work. GeminIQ's Insider Transactions feature pulls every Form 4 filing as it lands, which is exactly the data that confirms whether the academic pattern played out for a specific company — a spike in S-coded sales clustered right around the calculated expiration date. Price Variance shows the stock's actual post-filing price behavior over the same window, letting you compare what happened to this specific company against the broad, historical average researchers have documented, rather than assuming the average applies here by default.

Frequently Asked Questions

Is a lockup period an SEC rule?

No. It's a private contract between the company's underwriters and its pre-IPO shareholders, disclosed in the S-1 but not required or set by SEC regulation. Rule 144 and Rule 701 are the separate federal rules that govern when restricted shares become legally eligible for resale, and the contractual lockup is usually the tighter constraint of the two.

How long does an IPO lockup usually last?

180 days is the most common duration, though 90-day lockups and tiered structures — partial releases at 90 days, an intermediate point, and the full 180-day mark — both appear regularly. The exact terms and share counts are disclosed in the S-1's "Shares Eligible for Future Sale" section.

Can a lockup period be extended?

Yes. Many agreements automatically extend if the company releases earnings or discloses material news within a defined window — commonly the final 15 to 17 days — before the scheduled expiration, pushing the date out to roughly three business days after that disclosure.

Does the stock always fall when a lockup expires?

No individual outcome is guaranteed. But academic research going back to a 1,948-agreement study published in the Journal of Finance has consistently found an average negative abnormal return and a sustained increase in trading volume around lockup expiration dates across many companies, even though the date is public information well in advance.

The date is never a secret. What most investors miss is that it's rarely fixed either — and reading the S-1's actual lockup language is the only way to know which date, extended or not, actually applies.

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Sources: Field, Laura Casares and Gordon Hanka, "The Expiration of IPO Share Lockups," Journal of Finance, Vol. 56, No. 2 (2001). Lockup terms and release dates for the three 2025 listings are drawn from each company's prospectus and subsequent public announcements; CoreWeave's earnings-triggered termination and Circle's early-release tranche are documented in contemporaneous reporting on 2025 IPO lockup expirations, and Figma's price-condition early release and extended lockup structure in Sherwood News, September 2025. Verify any specific date against the company's own 424B4 and 8-K filings on SEC EDGAR before acting on it. Post-filing returns for CoreWeave (CIK0001769628), Circle (CIK0001876042) and Figma (CIK0001579878) are GeminIQ's own, measured cumulatively from each company's Q2 2025 10-Q filed date at one, two and three months; n=3 and no base rate is claimed from it.

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Disclaimer: The content in this blog is for educational and entertainment purposes only and does not constitute financial, legal, or tax advice. Investing involves risk, including the loss of principal. The views expressed are my own and not intended as financial advice or a guarantee of future performance.