According to sources cited by The Information, Anthropic plans to file its IPO prospectus after Labor Day, with a potential listing window in late September or early October. Reuters has reported on this. Earlier this year, the company submitted confidential listing documents to the U.S. SEC and is racing to debut alongside OpenAI. Goldman Sachs, JPMorgan, and Morgan Stanley are reportedly leading the underwriting.

The plan considers allowing existing shareholders to sell shares in the offering and evaluates a lock-up period longer than the usual 180 days. SpaceX and Cerebras did not allow existing shareholders to cash out during their listings this year; after the first unlock this month, SpaceX's circulating supply significantly increased. Anthropic has raised at least $130 billion for computing power needs, and reports suggest the offering size is expected to exceed SpaceX's approximately $86 billion financing in June. It is still unclear how much will be new shares versus existing shares.

The confidential S-1 review clock was initiated around June 1. The public prospectus will be the first complete audited financial statements, risk factors, and voting structure explanation. Reports indicate that the founders plan to set up high-voting shares, with public shares having almost no operational control; a public trust still holds a seat in governance. The private valuation was reported to be around $965 billion after the May round, and there is market discussion about a trillion-dollar opening. The market predicts a greater than 70% probability of an October listing.

OpenAI is leaning towards 2027, with internal reasons including cash burn, a commitment to over $600 billion in computing power by 2030, and preparation of financial statements. Whichever company lists first will provide a valuation anchor for investors like Amazon and Google. The public prospectus does not equate to a completed pricing, as roadshows and windows still fluctuate with the stock market.

Mechanically, this is a timeline for issuing to hedge the hunger for AI stocks. Buyers are institutions looking to grab the first trillion-dollar model company; sellers are companies and existing shareholders wanting to open the public market before computing bills arrive. Funds are rotating from private rounds into exchange subscriptions, and the lock-up period determines the supply slope after listing. Beneficiaries are existing shareholders who can sell shares in the offering and the underwriting syndicate; those under pressure are management who must disclose gross margins, computing commitments, and governance discounts according to public company standards, as well as OpenAI, which has not yet gone public and whose valuation anchor will be rewritten. The event driver is the movement of the prospectus from the confidential cabinet to the public directory after Labor Day.

Source: Public Information