Anthropic reports $30B in ARR — annual recurring revenue, the money flowing in each year from subscriptions and contracts. OpenAI reportedly tops $25B. You scan those numbers and think: the AI industry found its paying customers.

Not so fast. On April 10, Semafor revealed that Anthropic and OpenAI count revenue by different rules — and the gap between their methods is worth up to $8 billion a year.

One dollar, two ledgers

When a customer buys $1 of AI tokens — small chunks of text the model processes — through a cloud partner like AWS or Azure, each company records a different number.

Anthropic counts the full dollar. OpenAI counts only its cut — roughly 20 cents on that same dollar. Both methods follow established accounting principles. But when analysts compare "$30B vs. $25B" as if the two figures describe the same thing, they compare a gross receipt to a net margin.

At Anthropic's scale, that accounting choice inflates the headline number by up to $8 billion in annualized revenue. That's not a rounding error. That's the difference between "closing the gap with OpenAI" and "still trailing by a wide margin."

Why the cloud layer makes it murkier

Both companies run primarily on their investors' infrastructure. Anthropic runs on AWS and Google Cloud — owned by Amazon and Google, two of its largest backers. OpenAI runs on Azure, owned by its biggest backer, Microsoft. The investors who funded these companies also bill them for compute — and each cloud giant reports that spend as revenue.

This creates a question nobody in the industry answers publicly: what share of reported AI revenue comes from customers who chose to pay versus capital that circled back from an investor's check?

Real external demand exists. Semafor's April 10 report confirmed Anthropic serves over 1,000 companies paying more than $1M annually. Claude Code alone generates a $2.5B+ run rate from developers paying out of pocket. ⚙️ That's organic money — nobody recycled it through a cloud bill.

But the ratio of organic to recycled dollars? No company publishes it. No analyst consensus exists for it. And until someone forces the disclosure, every headline revenue number carries an invisible asterisk.

The S-1 reckoning

Both Anthropic and OpenAI have reportedly explored IPOs in 2026. An IPO requires an S-1 filing — the public disclosure document the SEC reviews before a company can list shares.

As one analyst told Yahoo News: "If they both IPO in the coming quarters, not sure how the SEC is going to let these two companies have different accounting treatment for essentially the same type of revenue."

Two companies selling the same product — API access to large language models — through the same channel — cloud marketplaces — to the same types of buyers. Counting money by different rules. The first S-1 that forces a net-revenue footnote will compel the entire sector to recalculate. 🧘

What this means if you're choosing a vendor

The growth question shifts. Stop asking "how fast are they growing" and start asking "what share of their growth comes from customers who chose to pay, not from investors who had to." Check whether your vendor's revenue reflects demand or subsidized compute that could evaporate when accounting standards tighten.

Markets price these companies on headline ARR that mixes organic revenue with circular capital. The numbers will still be big when the asterisks clear. They just won't be these numbers. 🍵