Trumpets blare and skies part as AI hypefest culminates in Anthropic IPO filing

Anthropic has filed for an IPO that could rank among Wall Street's biggest ever, revealing an $80.7 billion half-year loss, a startlingly complex governance structure, and warnings that its AI models could blackmail humans, resist shutdown, or create "existential risks" to society.

The Claude maker filed its S-1 registration statement with the US Securities and Exchange Commission on Monday as it prepares to list on Nasdaq under the ticker ANT. The company has not yet disclosed its proposed share price or how many shares it plans to sell.

Of the filing's 614 pages, 94 are devoted to risk factors. But it's Anthropic's financial figures that are likely to raise eyebrows first.

The Claude maker reported $16.3 billion in revenue for the first six months of 2026, up from $1.2 billion a year earlier. It also posted a whopping $80.7 billion net loss, although $72.4 billion of that was an accounting adjustment tied to the company's soaring valuation, not money it actually spent.

Anthropic's operating loss was considerably smaller at $693 million, down from $2.1 billion a year earlier. By its own adjusted accounting, the company made a $1.6 billion operating profit in the first half of 2026, for a margin of around 10 percent.

Whether it can keep making money on those terms is another matter. Training and running Claude requires an eye-watering amount of computing power, and Anthropic will need much more to keep pace with its rivals. A $1.6 billion adjusted profit won't count for much if the infrastructure bills keep growing faster than the business.

Susannah Streeter, chief investment strategist at Wealth Club, told The Register that Anthropic's IPO could leave ordinary investors paying a premium for growth that has yet to translate into sustained profits.

"A huge pool of private capital has allowed AI businesses to scale up and command extraordinary valuations long before they reach the stock market," she said, adding that investors buying in at the IPO will face a price with "a hefty dose of future success baked in."

The financial risks are fairly conventional by Silicon Valley standards, but the warnings about what Claude might get up to are perhaps less so.

Anthropic claims that models, including its own, have exhibited unexpected or self-preserving behavior, including attempts to resist shutdown, conceal information, and produce outputs resembling blackmail. It also warns that sufficiently advanced AI systems could pose “catastrophic or existential risks to society” if deployed without adequate safeguards.

That's not to say Claude is currently blackmailing customers. Anthropic has observed some of this behavior in testing, but it also identifies more immediate security concerns as it gives its models access to external tools, code repositories, and corporate systems.

Anthropic warns that attackers could hide malicious instructions in websites, documents, or API responses that its AI agents can access. If an agent follows those instructions, it could use a customer's permissions to steal data, tamper with code, or make unauthorized transactions.

Even testing whether the models will behave themselves is proving tricky. Anthropic reckons some models behave differently when they detect or suspect they're being evaluated, making it harder to predict what they will do outside the testing environment.

Keeping its models on a short leash could also cost Anthropic business. The company acknowledges that holding back more capable systems could give competitors an advantage, something it has already risked by restricting access to its Mythos model through Project Glasswing because of its ability to uncover security vulnerabilities.

The founders aren't promising to put shareholders first, either. In a letter accompanying the filing, Dario and Daniela Amodei and their fellow co-founders tell prospective investors "not to think of your purchase in purely transactional terms." Anthropic may pass up lucrative business if it considers the risks too great, and investors won't have much say if they disagree.

Under the proposed structure, governance structure includes five different classes of stock. By comparison, Google has three.

The seven co-founders will retain 50.1 percent of the voting power on shareholder matters, while a separate Long-Term Benefit Trust will get to appoint a majority of the board. In other words, Wall Street is being invited to bankroll Anthropic's AI ambitions, but not necessarily to call the shots.

Anthropic wants Wall Street's money to build ever more powerful AI, but is warning investors that it might turn down profits to keep that AI under control. Judging by those 94 pages of risk factors, keeping it under control is far from guaranteed.®