Anthropic's Fable 5 draws 11% of enterprise spend, clouding $2T IPO

Anthropic's flagship Fable 5 has captured just 11 percent of enterprise spending on its tools two months after launch, as customers shift to cheaper alternatives ahead of a potential $2 trillion IPO.

"Most people don't need to operate at the frontier," Miles Clements, a partner at Accel, which invested nearly $1 billion in Anthropic, said. He called the period when customers mostly chose flagship models "not a sustainable era."

Ramp data tracking 70,000 companies shows Fable 5's share of Anthropic spending has plateaued at roughly 11 percent since its June launch, while the cheaper Opus 5 — released in late July — has already overtaken the flagship in enterprise outlays. OpenAI's GPT 5.6, priced significantly below Fable 5, helped push the rival's annualized revenue above $40 billion, up 35 percent quarter over quarter.

The weak uptake lands as Anthropic prepares what could be the largest IPO in history — bankers have floated raising more than $100 billion at a $2 trillion valuation, potentially exceeding SpaceX's $1.77 trillion listing in June. Anthropic reported $65 billion in July annualized revenue, missing the most optimistic forecasts of $80 billion, and the company must prove the slowdown is temporary before its earliest possible October debut.

Cheaper models erode the frontier premium

The shift marks a structural break from the pattern that defined the first wave of AI monetization. Enterprise customers historically migrated to the most powerful available models, justifying the billions of dollars in training costs that frontier labs poured into each successive generation. Fable 5's weak adoption suggests that dynamic is reversing.

Anthropic's own Opus 5, positioned as more affordable and efficient, has already surpassed Fable 5 in enterprise spending since its July 25 release, according to Ramp. The company also cut pricing on Opus 5 as Chinese open-weight models from developers including Z.ai continue to undercut US labs on cost — Z.ai's GLM-5.2 is priced six times cheaper than comparable OpenAI and Anthropic offerings.

The political turbulence around Fable 5 compounded the problem. The Trump administration forced Anthropic to withdraw the model in early June over national security concerns, and it only returned online July 1 after approval. Ramp chief economist Ara Kharazian said data retention rules introduced by the administration also held back adoption, though analysts say price and performance now outweigh political factors in customer decisions.

The revenue concentration adds another layer of risk. APIs account for roughly 80 percent of Anthropic's revenue, meaning any enterprise budget cuts would amplify swings. The company's growth has been dramatic — July ARR of $65 billion is up from $47 billion in May and nearly seven times the $9 billion at the end of 2025 — but the deceleration from the most optimistic buy-side expectations triggered a global tech selloff. The Philadelphia Semiconductor Index fell nearly 5 percent on the day the ARR figure was disclosed, and the Nasdaq dropped another 1.33 percent the following session.

The $750 billion CapEx question

The stakes extend far beyond Anthropic. The four largest cloud vendors — Amazon, Microsoft, Alphabet, and Meta — have pushed combined annual capital expenditure from about $455.8 billion to nearly $750 billion over two years. Market consensus for 2027 puts that figure at $1.1 trillion to $1.4 trillion. If model-side revenue growth slows, the sustainability of that upstream spending comes into question.

Anthropic's internal projection of $1.9 trillion to $2 trillion in ARR by 2028 underpins the $2 trillion IPO valuation, roughly 10 times forward revenue. But the company's own Claude Code product — which drove its revenue surge past OpenAI earlier this year — is showing signs of deceleration. Tracked ARR for Claude Code reached $15.12 billion as of Aug. 10, up just 6.2 percent from the end of July, while OpenAI's Codex grew 20.8 percent in the same period from a smaller $8.83 billion base.

Kharazian acknowledged the difficulty of forecasting Anthropic's trajectory. "If you impute previous trends you expect Anthropic to own the market. But because OpenAI's newest model was so good and Fable underperformed, it's been the reverse," he said.

Anthropic has roughly 6,000 customers spending at least $100,000 annually and posted its first adjusted operating profit in the second quarter, with expectations of another profitable quarter in Q3. The company also hired Amir Salek, the founder of Google's custom chip program, as it prepares to build its own silicon. But with only two to three revenue update windows before a possible October listing, the market will scrutinize every data point for signs of an inflection rather than a blip.

This article is for informational purposes only and does not constitute investment advice.