When you think of enterprise AI, OpenAI is probably the first name that comes to mind. ChatGPT became a verb. Microsoft poured billions into integration. GPT-4 set the benchmark. And yet, according to fresh data from fintech firm Ramp, Anthropic has quietly overtaken its better-funded rival in the race for business customers.
Ramp’s May AI Index, compiled from expense data across more than 50,000 companies, shows that 34.4% of participating businesses are now paying for Anthropic products — compared to 32.3% paying for OpenAI. It’s the first time Anthropic has held the top spot.
The shift didn’t happen overnight. Twelve months ago, only 9% of businesses in the survey were spending on Anthropic. That figure has nearly tripled. Over the same period, OpenAI’s share actually dipped by a percentage point. While the Ramp dataset isn’t a perfect proxy for the entire market — it skews toward companies that use its spend management platform — the sample is broad and diverse enough to signal a genuine shift in the enterprise AI landscape.
OpenRouter’s independent rankings tell a similar story. On that platform, which samples a different user base, OpenAI last ranked above Anthropic in December 2025. Since then, Anthropic’s Claude models have steadily pulled ahead in usage share.
A Developer-First Blueprint
Anthropic’s rise didn’t come from flashy consumer products or broad marketing campaigns. It came from doubling down on developers and technical teams. Ramp economist Ara Kharazian, who compiled the index, put it plainly: “Start with a very technical customer base, focus on their needs, really succeed in execution and then start broadening out through tools like Cowork.”
That strategy mirrors the classic playbook of developer-first companies like Stripe and Twilio. By winning over engineers and data scientists first, Anthropic built organic adoption inside organizations. Those technical champions then became internal advocates, expanding usage across departments.
The launch of Claude’s “Cowork” feature, which lets users collaborate with AI in shared workspaces, appears to have been a key inflection point for broadening Anthropic’s appeal beyond pure technical users.
What This Means for the AI Market
The numbers raise an uncomfortable question for OpenAI: with a massive first-mover advantage, the ChatGPT brand, and the full weight of Microsoft’s enterprise distribution, why is it losing ground?
Part of the answer may be pricing and reliability. Anthropic has consistently positioned Claude as the safer, more predictable choice for enterprise workloads — emphasizing “constitutional AI” training methods that reduce hallucination rates and make outputs easier to audit. For compliance-heavy sectors like finance, legal, and healthcare, that message resonates.
OpenAI, meanwhile, has been fighting battles on multiple fronts: the ongoing Musk trial, internal governance questions, and pressure to monetize its consumer user base. Those distractions may have left the door open for Anthropic to quietly build relationships with the buyers who matter most — the ones signing six-figure contracts.
The Takeaway for Startup Founders
There’s a broader lesson here that extends well beyond the AI industry. Anthropic didn’t try to out-market OpenAI. It didn’t lead with consumer hype or brand awareness. It led with product excellence for a specific, influential audience and let the growth follow.
For startup founders building in crowded markets, the playbook is worth studying: identify the users who care most about quality and reliability, serve them exceptionally well, and use that beachhead to expand. It’s slower than chasing mass adoption, but it’s harder to disrupt.
Whether Anthropic can hold its lead is an open question. Ramp’s economist is skeptical about the advantage lasting, and OpenAI is likely to respond aggressively. But for now, the data confirms something the developer community has been whispering for months: in the enterprise AI race, the quiet contender just took the lead.
Source: TechCrunch — Anthropic now has more business customers than OpenAI, according to Ramp data
