Anthropic's IPO lock-up does not end on one day. The S-1 Anthropic filed on October 26 restricts directors, officers and most pre-IPO stockholders for up to 180 days after the prospectus date, and its seven co-founders and some larger holders for up to 365 days, but lets each group sell in steps long before that. Non-founder directors, officers and some employees may sell up to 10% of their locked shares from the first day of trading.
A lock-up is a promise by people who owned a company before its initial public offering not to sell, pledge or hedge their shares for a set time after it. Anthropic's filing says the underwriters requested its standoff terms, and its risk factors warn that sales after the offering, or the prospect of them, could push the share price down. The terms matter more now that the deal is taking shape: Anthropic plans to sell up to 552.9 billion yen, about $3.5 billion, of the offering to investors in Japan, Reuters reported on November 2, citing a filing.
Who signed, and what they cannot do
The filing describes two layers. Anthropic's directors, officers and "the holders of substantially all of our capital stock" are bound by market standoff agreements with the company, which bar sales, short sales, loans and options on their shares for 180 days. On top of that, the founders, directors, officers, some current and former employees and consultants, and some other stockholders, "including certain stockholders holding more than 0.5% of our fully diluted shares," signed lock-up agreements with the underwriters.
The underwriters' version is wider. It bars any "Transfer," which the filing defines to include hedges, swaps and other derivatives that pass on the economics of the shares, and it bars demanding a registration of locked shares. Goldman Sachs and Morgan Stanley, the two representatives of the 22 underwriters, may release any holder "in whole or in part at any time," and the filing adds that some releases "will trigger a pro rata release" for certain other holders.
Anthropic is locked too. Until the earlier of its first-quarter 2027 results or day 180, the company agreed not to sell new stock or file a registration statement without the representatives' consent, with exceptions that include employee equity plans, its convertible notes and stock issued in acquisitions.
When each group can sell
Each group's lock-up ends on whichever comes first: a results release or a fixed day count. For most holders the end is 6:00 a.m. ET on the second full trading day after Anthropic releases results for the quarter ending March 31, 2027, or the close of trading on the 180th day after the prospectus date. For the founders and the 365-day group it is the same point after results for the quarter ending September 30, 2027, or the close on day 365.
Who | Early sales | Fully free |
|---|---|---|
Non-founder directors, officers, some staff | 10% day one; 45% after FY26 results | Q1 2027 results or day 180 |
Some stockholders | 26% by day 76; 86% before full release | Q1 2027 results or day 180 |
Some holders over 0.5% | 30% at the 180-day point; 90.9% by Q2 2027 + 83 days | Q3 2027 results or day 365 |
Seven co-founders | 29% at Q1 2027 results or day 180 | Q3 2027 results or day 365 |
Source: Anthropic S-1, "Underwriting" and "Shares Eligible for Future Sale". Percentages are cumulative shares of each group's locked holdings, by a SaasBuzz calculation from the filing's steps.
The steps are small and frequent. The "some stockholders" group may sell 6% on each of days 27 and 48 after the prospectus date and 7% on each of days 62 and 76, then 12.5% after Anthropic's results for fiscal 2026 and 9.5% on each of the next five dates, 13 to 69 days after those results. The 365-day group gets the same early steps at exactly 30% of the size, 1.8% where the other group gets 6%, then larger steps keyed to the first and second quarters of 2027.
A worked timeline
Anthropic has not priced the offering, and the prospectus date that starts the clock is not set, so the timeline below counts from that date and from results releases rather than from calendar dates. "Day 27" means the 27th day after the prospectus date. Where a step falls on a day that is not a trading day, the filing moves it to the next trading day.
When | 180-day group | 365-day group |
|---|---|---|
Day 27 | 6% | 1.8% |
Day 48 | 12% | 3.6% |
Day 62 | 19% | 5.7% |
Day 76 | 26% | 7.8% |
FY26 results | 38.5% | 11.55% |
FY26 + 13 to 69 days | 48% to 86% | 14.4% to 25.8% |
Q1 2027 or day 180 | 100% | 30% |
Q1 + 34 to 76 days | 100% | 35.6% to 52.4% |
Q2 2027 results | 100% | 59.4% |
Q2 + 27 to 83 days | 100% | 65.7% to 90.9% |
Q3 2027 or day 365 | 100% | 100% |
Source: Anthropic S-1, pages 308 to 309 and 322 to 323; cumulative share of each group's locked holdings that may be sold, by SaasBuzz calculation. The ranged rows are five or four steps, each 14 days apart.
Across all groups, the filing's own schedule lists 23 separate dates on which shares become available for sale. Most of the dated steps come in runs spaced 14 days apart.
How employee equity is treated
Employees meet the lock-up through restricted stock units (RSUs) and options. Some RSUs settle at the IPO itself: shares whose service condition was met by the prospectus date, and whose performance condition is met when the registration statement takes effect, are issued net of shares held back for taxes, the filing says.
The non-founder directors, officers and "certain of our current and former employees and consultants" in the first group may sell up to 10% of their locked securities from the first trading day and up to an additional 35% from the second full trading day after the fiscal 2026 results. Shares those holders received when an award vests, settles or is exercised during the lock-up stay locked, but founders, directors, officers and current or former employees may sell in "sell to cover" trades to pay the exercise price or taxes that vesting creates.
Two securities rules sit underneath the contracts. Rule 701, as the filing summarizes it, lets holders of shares from compensation plans resell under Rule 144 without its holding period, but only from 90 days after the prospectus date. Anthropic also plans to file Form S-8 registrations for its equity plans promptly after the offering takes effect, which the filing says makes those shares eligible for sale subject to vesting and the lock-ups.
Rules that apply after the lock-up
When a lock-up ends, SEC Rule 144 still governs resales of restricted shares. Under the rule's text, once a company has reported to the SEC for at least 90 days, "a minimum of six months must elapse" between acquiring restricted shares and reselling them. Affiliates may sell in any three months no more than the greater of 1% of the shares outstanding or the average weekly trading volume over the four preceding weeks, the S-1 says.
The co-founders carry one more variable. The filing says each has pledged to dedicate 80% of their personal equity in Anthropic to philanthropic causes, calls those commitments "voluntary, revocable," and says donated shares and any later sales by recipients are subject to the lock-ups. Founders may give shares to charities and estate-planning vehicles during the lock-up, but the recipient must sign a lock-up agreement.
What the schedule means for buyers in the offering
The lock-ups bind people who held Anthropic stock before the IPO. Shares bought in the offering by investors who signed no lock-up are outside them, in the United States and in Japan alike, and the agreements expressly free shares that a lock-up party who is not an officer or director buys from the underwriters or on the open market after the offering closes. The prospectus says the offering includes public offerings in Japan, Australia, Canada, parts of the European Economic Area, Switzerland and the United Kingdom, and says Anthropic has applied to list the stock on the Nasdaq Global Select Market, under the symbol ANT, and does not currently intend to list it on any exchange in those other jurisdictions.
The design trades one large expiry for many small ones. Anthropic's own risk factors say that sales "as lock-up restrictions end or pursuant to registration rights" may cause the share price to fall, and the schedule spreads those possible sales over a year, with the larger releases tied to the days after results are public. How many shares each step covers is still unknown: the October 26 filing leaves the share counts and the percentage of fully diluted shares in each group blank.
Questions readers ask
How long is Anthropic's IPO lock-up?
Up to 180 days after the prospectus date for directors, officers and most stockholders, and up to 365 days for the seven co-founders and some holders of more than 0.5% of fully diluted shares. Each group's restriction can end sooner, two full trading days after a set results release, and each can sell part of its shares in earlier steps.
Can Anthropic employees sell shares on the first day of trading?
Some can. The filing lets non-founder directors, officers and certain current and former employees and consultants sell up to 10% of their locked securities from the first trading day. Other pre-IPO holders are generally covered by the 180-day market standoff agreements that bind the holders of substantially all of Anthropic's stock, and Rule 701 sales of plan shares start 90 days after the prospectus date.
Can the lock-up be lifted early?
Yes. Goldman Sachs and Morgan Stanley, as representatives of the underwriters, may release any locked shares "in whole or in part at any time," according to the S-1. Anthropic may release holders from its own market standoff agreements, generally only with the representatives' consent. Some releases trigger a matching pro rata release for certain other holders.
Sources
Anthropic, PBC, Form S-1 registration statement, filed October 26, 2026: "Underwriting", "Shares Eligible for Future Sale" and "Risk Factors"
17 CFR 230.144, Rule 144, Electronic Code of Federal Regulations
Reuters, via KFGO: Anthropic plans to sell $3.5 billion of shares to Japan investors in IPO, November 2, 2026
