For years, OpenAI felt untouchable; it had the name recognition, ChatGPT, and the cultural moment. 

But something has changed in the business world, and the data is hard to ignore. For the first time ever, more companies are paying for Anthropic than for OpenAI.

That’s the finding from Ramp’s May 2026 AI Index, a monthly snapshot pulled from real expense data across tens of thousands of businesses. 

Numbers 

According to Ramp’s data, 34.4% of participating businesses now pay for Anthropic services, while OpenAI sits at 32.3%. 

Just 12 months ago, in May 2025, only 9% of businesses were paying for Anthropic products. That number jumped by 26 percentage points in a single year. 

Meanwhile, OpenAI’s share actually dipped by 1% over the same period. Anthropic nearly tripled its business customer base in one year.

Also read: OpenAI Is Having a Rough 2026 – And It Shows

Dataset

Ramp’s index covers more than 50,000 companies, a large, diverse sample. But it’s still just one lens on the market.

Other datasets are showing the same trend; on OpenRouter’s leaderboard, which tracks a completely different sample of users, OpenAI last ranked above Anthropic back in December 2025.

That’s nearly half a year of Anthropic leading in that space, too.

Anthropic

So how did a company that started as the “safety-focused AI lab” end up winning over the business world?

Ramp economist Ara Kharazian has a clear answer: Anthropic started narrow and went deep.

“What Anthropic did worked really well,” Kharazian told TechCrunch. “Which was, start with a very technical customer base, focus on their needs, really succeed in execution, and then start broadening out.”

In other words, Anthropic didn’t try to be everything to everyone right away. It zeroed in on high-demand sectors (finance, tech, and professional services) and earned a strong reputation there first. 

Then it expanded outward. That expansion has included tools like Cowork, which helps broaden Anthropic’s reach beyond its original technical audience. 

OpenAI 

This isn’t a complete collapse for OpenAI. Kharazian noted that OpenAI still holds an advantage among companies outside those high-adoption sectors. 

But even that edge has been shrinking month after month. “Anthropic has already been in the lead amongst the high adoption groups like finance, tech, professional services,” he explained.

“It’s across the other firms where OpenAI still has a lead, but that has been shrinking over the past couple of months.”

In fast-moving industries like AI, momentum matters. And right now, momentum favors Anthropic.

Kharazian himself isn’t betting on Anthropic’s lead being permanent. He laid out his skepticism in a blog post, pointing to how quickly AI changes.