Anthropic has pulled ahead of OpenAI where it matters most for revenue: the workplace.

For the first time, more U.S. businesses are paying for Anthropic’s Claude than for OpenAI’s ChatGPT. The shift, recorded in April 2026, marks a turning point in a race that OpenAI had dominated for two years. It also raises a practical question for investors: how do you profit from it when neither company is publicly traded?

The numbers behind the shift

Anthropic adoption among U.S. companies rose to 34.4% in April 2026, while OpenAI slipped to 32.3%, according to the latest AI Index from Ramp, a corporate spend-management platform. Anthropic’s share climbed 3.8 points in a single month, while OpenAI’s fell 2.9 points. Google trailed both at just under 10%.

“[The results mark] a stunning reversal in the competitive market dynamics for AI model providers,” wrote Ara Kharazian, the Ramp economist who compiles the index.

A 2025 market study from venture firm Menlo Ventures pointed the same way. It pegged enterprise spending on large language models at roughly $8.4 billion and named Anthropic the leading provider, with about 32% of the market against 25% for OpenAI — down from the 50% OpenAI commanded in 2023.

The driver is software development. Claude has become the default model inside many coding tools, and developer budgets have followed. For a generation of engineers, Claude is now the standard alternative to OpenAI’s chatbot — a reversal few predicted when ChatGPT launched.

Why you can’t buy Anthropic or OpenAI directly

Here is the catch. Both Anthropic and OpenAI are private companies. Their shares do not trade on the Nasdaq or the New York Stock Exchange, and retail investors cannot buy them through a standard brokerage account.

Both labs are widely expected to pursue initial public offerings, and each has been valued in the hundreds of billions of dollars in private funding rounds. But no IPO has been scheduled, and pre-IPO shares are generally restricted to institutions and accredited investors.

That leaves one realistic route for most people: the publicly traded Big Tech companies that have already bet on these labs.

Three stocks that give you indirect exposure

  • Amazon (AMZN) is Anthropic’s largest financial backer. After an initial $8 billion commitment, Amazon agreed in April 2026 to invest up to $25 billion more, and Amazon Web Services is Anthropic’s primary cloud provider. Much of Claude’s growth flows back to Amazon through cloud-computing demand.
  • Alphabet (GOOGL) is also a major Anthropic backer, committing up to $40 billion in April 2026, much of it in computing power. It can win twice here: as an Anthropic shareholder and as an infrastructure vendor.
  • Microsoft (MSFT) remains OpenAI’s principal partner, with a multibillion-dollar investment and deep product integration across its Office and Azure businesses. An OpenAI rebound would likely show up here first.

For investors who want broader coverage than a single name, money.it has surveyed the AI stocks Wall Street analysts favor, a list that spans chipmakers, cloud providers, and software firms exposed to the same trend.

What this means — and what to watch

The headline is real, but it needs context. Ramp’s data covers businesses that use its expense platform, a base that skews toward startups and fast-growing firms. OpenAI says it still expects to out-earn Anthropic in total revenue this year, partly because large enterprise contracts are not paid by credit card and may not register in Ramp’s numbers.

There is a second caveat. Big Tech’s Anthropic gains can look larger than they are. Alphabet booked roughly $28.7 billion of its record first-quarter profit simply from marking up the value of its Anthropic stake — a paper gain on a private company whose price Alphabet itself helps to set, not cash earned from selling Claude.

In other words, a one-month lead is not a durable advantage. As Warren Buffett reminded shareholders when asked about AI, technology shifts can be fast and unforgiving, and today’s winner is not guaranteed to be tomorrow’s.

For now, the takeaway for investors is straightforward. You cannot own Anthropic or OpenAI outright, but you can track the contest through Amazon, Alphabet, and Microsoft. Watch three things in the coming quarters: cloud-revenue growth at Amazon and Alphabet, any concrete IPO timeline from either AI lab, and whether Anthropic can hold its lead beyond a single month.

The AI model wars just produced their first true upset. The companies winning it are private — but the ways to invest around it are not.