Anthropic Weighs Letting Insiders Sell on IPO Day While Locking Others Up Past Mid-2027

Since The Information's report on Thursday, August 27, that Anthropic is weighing an unconventional IPO lockup structure, more details have surfaced about how the AI company plans to manage a listing that could top SpaceX's record-setting debut.

The basic idea, according to The Information and confirmed in subsequent coverage by TradingView and Reuters: Anthropic would let some existing shareholders sell a portion of their stock the day the company goes public, while locking up the rest of insider holdings for well beyond the customary 180 days. Some shares reportedly wouldn't be free to trade until mid-2027, according to the Yahoo Finance and Motley Fool analysis of the report.

The Information said it could not confirm the size of that day-one selling tranche or who would be included, whether early investors, senior executives, rank-and-file employees, or some combination. Anthropic did not immediately respond to a Reuters request for comment, and the plans are described by The Information as not final.

A Break From SpaceX's Playbook

The structure would put Anthropic in different company than SpaceX and Cerebras Systems, both of which completed primary-only IPOs this year with no existing-holder sales, according to TradingView. CoreWeave and Figma, by contrast, did include secondary sales when they went public.

SpaceX priced its June 2026 Nasdaq offering at $135 a share, selling 555.56 million new shares for $75 billion before underwriters exercised an overallotment option that pushed the total to roughly $85.7 billion, valuing the company at about $1.75 trillion to $1.77 trillion, according to TradingView. Elon Musk's stake was locked for 366 days with no early release, and the rest of SpaceX's pre-IPO holders became eligible to sell in stages tied to earnings reports and fixed dates rather than a single cliff.

That staggered approach still produced volatility. According to WMBD Radio, citing Reuters, SpaceX's first lockup expiry in August more than doubled the number of SpaceX shares trading publicly, with another 12.9 billion shares scheduled to unlock by mid-2027.

Why Anthropic Might Want This

The Motley Fool's analysis frames Anthropic's proposed structure as an attempt to avoid exactly that kind of cliff-edge dump. A standard lockup expiration functions like a delayed sell order, dumping a wave of new sellers onto the market on a single date, which can push the stock down. Uber's 2019 lockup expiration is the textbook cautionary tale, and KuCoin's reporting points to that same episode as the reason for Anthropic's approach.

By letting a portion of shares trade immediately and stretching the rest of the lockup well past 180 days, Anthropic would spread out selling pressure over a longer window instead of concentrating it into one event. KuCoin also reported that Anthropic plans to require rank-and-file employees to sell only through preset 10b5-1 trading plans, pre-scheduled arrangements that specify sale dates and quantities in advance, rather than the open post-earnings trading windows most companies use.

The structure lets some insiders get liquid on day one, cashing in at whatever price the IPO euphoria produces, while ordinary employees and other shareholders wait more than a year. The Information could not confirm which insiders land in which bucket, and until Anthropic's public S-1 filing spells it out, nobody outside the company knows for certain.

Governance Without a Public Voice

KuCoin also reported that Anthropic's IPO structure will preserve founder control through super-voting shares and a dedicated trust, with no board-control concessions offered to public investors. That's not unusual for tech IPOs. Meta and Google both went public with dual-class structures, but it means retail buyers of Anthropic stock would have essentially no say in company decisions regardless of lockup terms.

The Numbers Still Don't Match

The valuation figures floating around remain inconsistent. TradingView reported bankers have discussed an IPO valuation of $1.5 trillion, just below SpaceX's pricing-level figure, while The New York Times has reported the offering could value Anthropic at $2 trillion. KuCoin's figures, drawn from an August report, put the range even wider, between $1 trillion and $2 trillion, with a raise potentially exceeding $60 billion. None of these are locked in. Anthropic's Series H round in May 2026 valued the company at $965 billion on $65 billion raised, and Anthropic has raised at least $130 billion total to fund its compute buildout, according to WMBD Radio's citation of the Reuters report.

Anthropic's public S-1 filing, whenever it lands, is what will settle the actual numbers: how many shares get sold at listing, how long the extended lockups run, and who exactly is eligible for day-one liquidity. Until then, every figure in circulation is a banker's estimate or a reporter's characterization of a plan Anthropic itself has not confirmed.