The rivalry between leading U.S. AI firms OpenAI and Anthropic is heating up. Recent reports indicate that Anthropic is swiftly gaining ground on OpenAI's paid user segment. Insights from credit card transaction analysis firm Indagari reveal a consistent month-over-month increase in both the number of paid users and revenue for Anthropic's flagship model, Claude. Since January 2026, revenue in this category has surged by roughly 75%. Indagari's findings are derived from hundreds of billions of anonymous credit card transactions involving 28 million U.S. consumers, spanning weekly data from 2025 up to May 10, 2026. Echoing this trend, DataCamp, an AI-focused online education platform, has observed a similar uptick, noting a significant rise in user interest in Claude this year. In fact, Claude has emerged as the most searched term on DataCamp's website, outpacing even the broader term 'AI'.