Lock-ups, founders and fast entry: how Anthropic’s shares will reach the market

What happened

What happened (fact)

Anthropic filed its S-1, the prospectus needed for a US listing, on Monday 26 October (14:00). For background, our earlier explainer (27 October) covered its profits and losses.

As of 30 October (EDGAR checked at 20:24), there was still no amended filing (S-1/A), so the price range, share counts, float and raise size are blank (S-1, p. 19).

Shares reach the market three ways.

1. Insiders selling in the IPO. Co-founders Tom Brown, Jack Clark, Jared Kaplan, Sam McCandlish and Christopher Olah are named as selling stockholders. How many each sells is blank (pp. 290–292). Anthropic receives no money from those sales (p. 19).

2. Lock-ups that open in stages. The lock-up unwinds in steps (pp. 322–324):

• Non-founder directors, officers and some staff and consultants: up to 10% from the first trading day, then up to a further 35% after the 2026 annual results.
• ”Certain of our stockholders”: 6% on each of days 27 and 48, then further steps.
• Certain holders of more than 0.5%: 1.8% on each of days 27 and 48, then further steps until the Q3 2027 results or day 365.
• The seven co-founders: no release until the Q1 2027 results or day 180, then up to 29%.

The lead banks, Goldman Sachs and Morgan Stanley, can release shares early at any time (p. 324). The filing lists “the anticipation of lock-up releases” among share-price risks (p. 115).

3. Suppliers that can take shares. Amazon, Google, Broadcom and AMD can be issued non-voting Class N shares under their financing deals (pp. 164–169), and Google and Broadcom have registration rights to resell (pp. 300–302). Google can also buy up to $10 billion of Class N stock at the IPO price (p. 169). Each is an interested party: a supplier that holds or will hold Anthropic shares, and Amazon, Google and Broadcom also lend to it through convertible notes (pp. 164–169, 301). So are the underwriters, whose affiliates arrange and act as agents for Anthropic’s credit facility (p. 325).

Do index funds have to buy?

What happened (fact)

An index fund copies a list of companies; each index sets its own entry rules.

• Nasdaq-100: since 1 May 2026, a fast entry rule admits an IPO that would rank among its 40 largest companies, “typically” after 15 trading days.
• Russell and CRSP: large IPOs can be added from the fifth trading day.
• S&P 500: there is no fast track. In June 2026, S&P kept its rule that a company must trade for at least 12 months first.

Whether Anthropic qualifies depends on its value, float and voting rights at listing, all still unknown. Russell also tests whether at least 5% of voting rights are in public hands (unless lock-up expiries should lift that within a year) and counts non-voting shares as no votes; with the founders’ single Class F share holding a fixed 50.1% of votes (p. 290), that can’t be judged until share counts are filed.

The “set up for index buying” argument

What @nodiligence thinks (his view)

In a post and X article on 27 October (02:30), the account @nodiligence called Anthropic “probably the best business in AI right now” but said he “still wouldn’t touch it on day one”. In his view, “the whole thing is set up for suppliers and insiders to sell into the index buying”. He expects early buyers to lose out before the lock-ups ease.

What happened (fact)

Most of the filing details he cites check out. His index buying on “days 5, 10 and 15” is partly right: day 10 is Nasdaq’s announcement, not a purchase. The intent can’t be verified, and the S-1 never mentions indexes. His float and raise figures aren’t in the filing, so we don’t print them, and his 18 November pricing date is an assumption; none has been filed.

What Chamath Palihapitiya thinks (his view)

Chamath Palihapitiya, whose firm Social Capital posted a bullish S-1 thread on 26 October, shared the piece on 27 October (17:18) with “Good read…”. He and his firm are interested parties.

What Lukas Gruber thinks (his view)

Investor Lukas Gruber posted on 27 October (19:51) that AI start-up Instinct is “currently raising @ $30b”. His profile links to Street, which calls itself a secondary market for private-company shares, so he is an interested party; the site doesn’t state his role. Jason Calacanis, who lists Amazon, an Anthropic shareholder, among stocks he owns (19 October) and so is an interested party, quoted the post: “What their revenue?”

What happened (fact)

As of 30 October, we found no company or major-outlet report of a $30 billion round. Instinct’s last confirmed valuation is $10 billion (28 September; Reuters, TechCrunch).

Who should get frontier AI?

What @TMTLongShort thinks (his view)

On 27 October (12:41), @TMTLongShort, a pseudonymous X account and commentator who describes himself as a tech investor, argued that the US should restrict other countries’ access to frontier AI so AI profits stay in the US.

What Luke Gromen thinks (his view)

Replying at 14:22, Luke Gromen, an interested party who runs the paid FFTT research letter, asked: “If I am anyone but US, why would I then not go with China on this?” His point is that China may spy, but it lets other countries keep the economic gains at home. He cites no data.

What happened (fact)

Anthropic’s filing says that in September 2025 a Chinese state-sponsored group used its Claude Code tool to try to break into about 30 targets (S-1, p. 46).

What to watch next

• The S-1/Athe price range, share counts, float and lock-up percentage.
• The pricing dateit fixes every lock-up release date.
• Index noticesNasdaq-100 ranks a new listing on its seventh trading day and announces after the tenth.
• Google’s $10 billion optionwhether Google uses it at the IPO.

In summary

Insiders can sell early, in stages; some index funds may buy within weeks. How much of either stays unknown until an S-1/A is filed.

Educational only: not a recommendation to buy, sell, avoid or time a purchase of Anthropic shares, any index fund, any leveraged fund or any other investment. The prospectus is preliminary, and figures can change.

This is not financial advice.