Anthropic's $16.3 Billion Run Reveals Two Cracks OpenAI Could Exploit

Anthropic booked $16.3 billion in revenue in the first six months of 2026 — a 1,300% year-over-year jump, just five years after its 2021 founding. Yet analysts poring over the company's newly public S-1 already see two places where rival OpenAI could hold the upper hand when it files its own prospectus, likely sometime in 2027: revenue growth and business diversity, particularly on the consumer side.

How fast is Anthropic actually growing now?

The topline numbers are historic by any standard. Anthropic's revenue was $41 million in 2023, grew 841% to $386 million in 2024, and jumped 1,088% to $4.6 billion in 2025.

"A company hitting this kind of scale this quickly is unprecedented," Aman Verjee, General Partner and Founder of Practical Venture Capital, told Fortune. Other analysts Fortune spoke to called the growth "stunning" and "extraordinary."

But the deceleration is already visible. The S-1 doesn't include third-quarter results directly, yet it notes revenue was 86 times its Q4 2024 level — a detail spotted by Fortune's AI editor Jeremy Kahn. Since Q4 2024 revenue was $197 million, that implies Q3 2026 revenue of roughly $16.9 billion. That works out to a 47% quarter-on-quarter increase from Q2 to Q3 — a sharp drop from the 132% growth between Q4 2025 and Q1 2026, and the 144% increase between Q1 and Q2 2026.

Anthropic itself isn't sugarcoating it. "We do not expect our revenue will continue to grow at comparable rates, and we cannot assure you that it will continue to grow at all," the S-1 reads. The company attributes its hypergrowth to "early-stage adoption dynamics, the nascency of the AI market, and rapid initial customer expansion," and warns growth "may not be sustainable over time, and may decline significantly and more rapidly than we anticipate" as the market matures.

OpenAI, by contrast, appears to be accelerating. Based on leaks and executive comments, sources expect OpenAI's S-1 to show faster top-line growth. In August, CFO Sarah Friar told investors the company now makes more money from enterprise customers than consumers, CNBC reported. And The Information reported this week that software engineers are increasingly choosing OpenAI's models after price cuts made them among the most affordable on the market.

Anthropic is fighting back on price — cutting costs and offering promotional discounts — while signing billion-dollar compute deals that may not pay off, as Fortune's Jeremy Kahn and Sebastian Herrera reported. That raises a question investors are asking openly: is AI turning into a race to the bottom, with thinning margins for both companies?

"Extraordinary revenue growth doesn't necessarily trend into extra extraordinary investment returns," Jonathan Tower, Founder and Managing Partner of venture firm Catapult, told Fortune. "My broader concern is that investors are confusing the magnitude of the AI opportunity with the profitability of its participants. AI could become the most consequential technology of our lifetime and still produce some of the most spectacular investment losses of our generation."

Why could OpenAI's consumer business be a hidden strength?

Here's the irony: OpenAI spent most of this year racing to catch up to Anthropic's enterprise business, yet investors see its consumer operation as a potential edge.

OpenAI has a "strong consumer brand and presence," Verjee said. That's an "advantage" that could translate into higher margins, Tower added.

The consumer push has real numbers behind it. This month OpenAI reported 100,000 advertisers signed up to serve ads in ChatGPT, and this week it debuted a new ad format featuring multiple images.

Hardware could compound that. OpenAI's forthcoming family of devices, designed by Jony Ive, could extend consumers' relationships with ChatGPT into the physical world and entrench them in an Apple-like ecosystem of AI assistants. The company has promised to disclose more details by the end of the year.

Anthropic admits the gap. Its S-1 references unnamed competitors with "stronger consumer-facing businesses, larger consumer user bases, more established brands, broader distribution, or deeper customer relationships" — companies that could leverage those relationships to build enterprise businesses and "compete more effectively with us." Anthropic says it doesn't plan to go toe-to-toe in consumer, which "would require significant time and resources beyond our current plans."

What does the IPO timing mean?

"The timing of the IPO benefits Anthropic by allowing it to raise the most, the earliest, and to benefit from persistent equity market enthusiasm," James Gellert, Executive Chairman of financial intelligence firm RapidRatings, told Fortune.

His point cuts both ways: the success of Anthropic's public offering could be among the biggest factors in OpenAI's future success — for better or worse.