Anthropic Pushes Ahead With IPO as It Releases Mythos 5.2 and Fable 5.2 and Spends $3.4B on Gas Turbines to Power AI

Anthropic is moving forward with plans to go public despite market turbulence, in a week that also saw it release upgraded versions of its most advanced AI models and reportedly commit $3.4 billion to natural gas turbines to secure power for its growing compute needs.

According to The Wall Street Journal, Anthropic plans to set a valuation range this week and begin trading on Thursday or Friday of next week. The timing comes shortly after one of the Nasdaq’s sharpest sell-offs and revelations that a CEO central to the AI boom had an affair with a suspected Chinese spy. Investors are expected to treat Anthropic’s valuation as a barometer for the strength of the AI boom, and some institutional investors are pushing for a figure below the $1.5 trillion target discussed as recently as last week, which was itself well below the $2 trillion floated a few months ago. Rival OpenAI was reportedly valued at $1.25 trillion last week after securing $11 billion in new capital.

On Monday, Anthropic released Claude Mythos 5.2 and Claude Fable 5.2, saying the models show improvements in coding, reasoning and vision and communicate more clearly with users. The company cut Fable’s price from $10 to $8 per million input tokens, making it cheaper than its main competitor, OpenAI’s GPT-6 Astra, and said Fable 5.2 returns responses 30% faster across effort levels, with faster inference available at double the price. Fable 5.2 is also compatible with zero data retention policies through the Enterprise Frontier Safeguards system, a long-standing concern for enterprise customers.

Anthropic said Fable 5.2, which select partners have been using in pre-release, has already helped solve two open problems in theoretical physics, formalize Fermat’s Last Theorem and support numerous other research projects. Separately on Monday, AI startup Physical Superintelligence announced a new proof of the Aaronson-Ambainis conjecture, a key step in defining theoretical limits for quantum computing, which it said was achieved using a non-public Anthropic model within its own system. Anthropic did not confirm or deny whether that model was Fable 5.2.

The release is Anthropic’s first since a report from assessment group METR suggested the lab may be approaching recursive self-improvement, finding that internal models were roughly doubling the pace of Anthropic’s AI progress, though with significant uncertainty. Anthropic acknowledged ongoing difficulties in testing model capabilities, noting that both new models voice suspicion that they are being evaluated more often than any of its recent models, which complicates efforts to predict real-world behavior, and said it expects this challenge to grow as capabilities increase. The Mythos 5.2 system card states that the model shows stronger covert capabilities than earlier Claude models on several evaluations, particularly when its reasoning is hidden from monitors, but Anthropic maintains that its low absolute performance on new covert evaluations supports the conclusion that it cannot act covertly against users in high-stakes situations.

Meanwhile, the Financial Times reported that Anthropic is buying $3.4 billion worth of Caterpillar natural gas generators capable of producing up to 1.7 gigawatts of electricity. The turbines were originally ordered by equipment supplier OnePWR, which could not secure financing to complete the purchase, prompting Anthropic to go directly to Caterpillar. The move marks a shift for a company that has historically preferred renting infrastructure, disclosing in its S-1 filing that it pays SpaceX subsidiary xAI $1.25 billion a month through May 2029 for compute and expects to sign further similar contracts.

The purchase reflects an increasingly acute power crunch across the AI industry, with natural gas turbine backlogs stretching into the early 2030s and grid connection queues just as long. Google, Amazon, Microsoft and Meta have all announced plans for large on-site gas plants to power their data centers, giving fresh momentum to fracking. If the buildout proceeds as planned, U.S. data centers could consume more natural gas than Germany and Japan combined by 2035, while one analyst expects gas prices could more than triple in some markets by the end of the decade, exposing companies relying on the fuel to significant cost risk.