Anthropic has overtaken OpenAI in the number of paying business customers for the first time. Ramp’s latest AI Index, drawn from expense records of over 50,000 companies, shows 34.4% using Anthropic’s services in April, compared to 32.3% for OpenAI. A narrow lead. But one that underscores shifting priorities among corporate buyers.
The numbers mark a stunning reversal. Just a year ago, in May 2025, Anthropic reached only 9% adoption. Its share quadrupled over the next 12 months, while OpenAI’s edged up a mere 0.3 percentage point, according to TechCrunch reporting on Ramp’s data. Ramp economist Ara Kharazian highlighted the momentum: “Anthropic has already been in the lead amongst the high adoption groups like finance, tech, professional services.” OpenAI holds ground elsewhere. That edge, though, keeps shrinking.
Anthropic’s ascent ties directly to Claude Code. Companies flocked to the tool for software development tasks starting late 2025. Demand exploded in early 2026. Businesses cite superior performance in coding, reliability, and cost efficiency. Ramp data reveals Anthropic capturing over 70% of head-to-head matchups against OpenAI among first-time AI buyers—a pattern persisting from March reports on Ramp’s site. Claude’s focus on technical workflows resonates. Enterprises want agents ready for real work, not just chat.
OpenAI’s slip? A 2.9 percentage point drop in April alone. Ramp attributes it partly to businesses consolidating vendors or switching for better fit. An OpenAI spokesperson pushed back in Axios: “We are driving enterprise transformation at scale. These are not engagements where customers pay with a credit card.” Fair point. Ramp tracks card and invoice spends, missing big-ticket contracts. Still, the index mirrors billions in monthly AI outlays. It flags trends investors watch closely ahead of potential IPOs.
Look closer at sectors. Anthropic leads in information tech at 63% versus OpenAI’s 54%, finance at 52% to 46%, and professional services at 47% to 44%, per earlier Ramp breakdowns updated in April data on Ramp’s April post. VC-backed firms show 66% Anthropic adoption against 59% for OpenAI. Early adopters set the pace. Kharazian noted in prior analysis: “The pattern in our data is consistent: what early adopters do today, the broader market does a few months later.” That prediction hit.
Ramp’s methodology matters here. It scans actual payments from 50,000 U.S. businesses—midmarket heavy, not just Fortune 500. Overall AI adoption hit 50.4% in March, up from 35% a year prior. Half of Ramp’s clients now pay for some AI. Google lingers at low single digits; xAI below 2%. Volatility defines this market. Kharazian cautioned in Business Insider: “We have never seen a software industry as dynamic, where newcomers can disrupt market leaders in a matter of months.” Token costs rise. Compute shortages bite. Open-source options tempt.
Anthropic broadens beyond code. Tools like Cowork target legal, finance, research. Kharazian praised the playbook to TechCrunch: “What Anthropic did worked really well, which was—start with a very technical customer base, focus on their needs, really succeed in execution and then start broadening out.” OpenAI ignited the boom with ChatGPT. Consumer fame endures. Enterprise demands precision. Incentives differ too. Kharazian critiqued in Axios: Anthropic earns more from pricier tokens, nudging toward premium models even when cheaper suffice.
X buzzed today. Ramp’s Kharazian posted: “ANTHROPIC beats OpenAI in business adoption for the first time. per @tryramp data. Today’s update of Ramp AI Index shows 34.4% of businesses using Anthropic versus 32.3% using OpenAI.” TechCrunch amplified: Anthropic quadrupled adoption yearly. Posts from developers and analysts echo the shift—Claude as default for serious coding. Revenue whispers fuel talk: Anthropic at $30 billion annualized run rate, OpenAI $24-25 billion. Unverified. But directionally telling.
This flip challenges assumptions. OpenAI once dominated. No longer untouchable. Businesses split spend—79% of Anthropic users still pay OpenAI, per February Ramp data. Multi-vendor reality. Product teams take note. Prioritize execution for devs, governance, cost-per-task. Competition accelerates. Next month could flip back. Or cement Anthropic’s grip. Watch Ramp’s June numbers.
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