With both OpenAI and Anthropic still privately held and their financials largely opaque, investors and analysts are turning to secondary signals to gauge which lab is winning over corporate customers. Fresh data from Ramp, a major corporate card and expense management platform, suggests the race is far from settled and that OpenAI is clawing back ground among US businesses.

Ramp examined spending patterns from more than 70,000 American companies that use its bill pay and card products. These firms collectively spend billions of dollars and skew toward technology and high-growth sectors, making them an influential early indicator of enterprise AI adoption.

Earlier this year, Anthropic surged ahead on Ramp’s platform. In May, it captured about 41 percent of AI spend among Ramp’s paying business users, edging past OpenAI at roughly 39 percent. By July, Anthropic had widened that lead to nearly 44 percent, while OpenAI hovered around 40 percent, cementing the perception that Claude had become the preferred tool for many corporate buyers.

But Ramp’s latest internal analysis, shared by company economist Ara Kharazian, shows OpenAI growing faster so far in the third quarter within this customer base. While Ramp did not disclose absolute dollar figures, the shift in share growth suggests that new or expanding OpenAI deployments are beginning to close the gap.

The data comes with important caveats. It does not capture large enterprises that rely on other spend-management providers, such as traditional banks and card issuers. It also reflects only paid usage, not the vast universe of free experimentation with chatbots and APIs. Still, the sample is large enough to reveal a clear pattern: business loyalty to any single AI provider is fragile.

As each lab rolls out new models and pricing structures, companies appear willing to switch or diversify. Anthropic’s premium Fable tier, for example, targets specialized, higher-stakes use cases and commands a higher price. Its requirement to retain customer data for 30 days sparked concern among some privacy-conscious clients, even as others accepted the trade-off for advanced capabilities.

Ramp’s numbers also indicate that both OpenAI and Anthropic are likely growing revenue, regardless of who leads in share. The proportion of Ramp customers paying for AI tools has risen steadily, surpassing half of all businesses on the platform and continuing to climb. The message for investors is twofold: the enterprise AI market is expanding rapidly, but competitive advantage remains volatile and far from locked in.