ChatGPT is by far the most popular consumer-facing AI product, and OpenAI seems to have a similar lead among business users as well.
Ramp AI Index shows overall business AI adoption rose to 46.8% of businesses in January, a new high, with Anthropic surging and now used by 19.5% of businesses.
Anthropic adoption grew from 16.7% to 19.5%, one of its largest monthly gains since tracking began. One in five businesses on Ramp now pays for Anthropic—a year ago, it was one in 25. Meanwhile, OpenAI adoption slipped from 36.8% to 35.9%, giving back some of last month’s gains. Google held steady at 4.5%.
The Multi-Vendor Reality
The Ramp report explored whether Anthropic is gaining at OpenAI’s expense through three possible scenarios: businesses switching from OpenAI to Anthropic, existing OpenAI customers adding Anthropic alongside their current subscriptions, or new AI adopters choosing Anthropic over OpenAI from the start. Ramp said that the data pointed to the second scenario — both companies have nearly identical churn rates of around 4% per month, ruling out mass switching behavior. Meanwhile, about 79% of Anthropic’s customers also pay for OpenAI, indicating that Anthropic’s growth is driven by existing OpenAI customers adding a second provider rather than replacing their first.
Growing Overlap, Not Replacement
Today, 16% of businesses pay for both OpenAI and Anthropic. A year ago it was 8%. This overlap metric is often lost in simple market share analyses, but it may be the most important one to watch.
The findings suggest the race isn’t zero-sum—at least not yet. The market is young enough that businesses are buying from more than one model company. Different tools for different teams, different tasks. Engineers prefer one model, the sales team uses another, and the company pays for both.
Another read could be that businesses are experimenting with Anthropic as a second vendor and will eventually pick a winner. In this scenario, the overlap will shrink over time as firms consolidate on one vendor.
A Different Picture In API Usage
Interestingly, these subscription numbers tell a different story than enterprise API usage data. Menlo Ventures reported in December that Anthropic had overtaken OpenAI in the enterprise LLM API market, with a 40% share compared to OpenAI’s 27%. That metric specifically tracks API usage, while Ramp’s data appears to include all paid subscriptions—encompassing tools like ChatGPT Team and ChatGPT Enterprise alongside API access.
The divergence suggests that while OpenAI maintains broader adoption across business use cases (likely driven by ChatGPT’s familiar interface and consumer brand recognition), Anthropic may be winning among developers and technical teams building AI-powered applications through API integrations.
So Who Is Winning?
The market is young enough that multiple winners can coexist. Different tools serve different teams and tasks within the same organization. The 79% overlap between Anthropic and OpenAI customers suggests businesses see value in both platforms rather than viewing them as direct substitutes.
Whether this multi-vendor approach persists or consolidates remains the key question. For now, the data shows a rising tide lifting multiple boats—with overall AI adoption climbing to nearly half of all businesses, there’s plenty of room for growth across providers.
The real competition may not be between OpenAI and Anthropic, but between AI adopters and AI holdouts. At 46.8% adoption, there’s still more than half the market yet to embrace AI tools at all.