Per the May 2026 release of Ramp's AI Index, Anthropic's adoption in US businesses rose 3.8% in April to 34.4%, while OpenAI's adoption fell 2.9% to 32.3%. Ramp tracks spending patterns across more than 50,000 US businesses through their corporate card data, which makes it one of the better proxies we have for actual business AI spend.

This is the first time Anthropic has been ahead.

The trajectory matters more than the snapshot. A year ago, OpenAI commanded roughly 32% of business AI adoption. Anthropic stood at under 8%. In the twelve months since, Anthropic has quadrupled its share. OpenAI's share grew 0.3% over the same period.

That's not a competition. That's a category shift in motion.

What's driving it

One product: Claude Code.

A recent analysis estimated that 4% of all public GitHub commits worldwide are now being authored by Claude Code — double what it was a month earlier. That's not a typical adoption curve. That's the kind of growth you see when a product hits something close to product-market fit at the same moment the underlying capability becomes good enough to actually trust.

The pattern: developer adopts Claude Code for their own work, ships better, recommends it internally, the team adopts it, eventually procurement notices an expense pattern and either ratifies the spend or shifts the contract. Multiply by however many software teams exist at every business in America, and you get Anthropic's quadrupling.

What's interesting is what's not driving it. Anthropic's consumer-facing product is still smaller and slower-growing than ChatGPT. The bet that won the business adoption race was the developer-facing product, not the consumer one.

Why I think the lead is fragile

Three reasons.

One: it's concentrated in a single product line. If Claude Code's growth slows for any reason — model capability flattening, a Cursor or Copilot feature parity, pricing pressure — the underlying adoption story has nothing else to lean on. OpenAI's adoption is more diversified across consumer, enterprise, and developer surfaces. A 32% diversified position may be more durable than a 34% concentrated one.

Two: the pricing model is the engine and the risk. Claude Code is priced on tokens, which means a customer's bill scales with their use. That's great when use grows. It's brutal when customers hit their internal threshold of "this LLM bill is now larger than our cloud bill" and start optimizing. Multiple Anthropic customers I've watched go through this curve hit a moment where token-based pricing becomes the thing they're managing against rather than capability. When that happens, alternatives suddenly look more attractive.

Three: compute is the constraint. Anthropic's growth has run ahead of their inference capacity for two quarters now. If you've been on the API recently you've seen the rate-limit hits and the occasional capacity-related fallback. That's a real constraint. OpenAI has Microsoft. Anthropic has Amazon and Google, but neither relationship is as deep as Microsoft-OpenAI is.

For builders

• If you're choosing an AI stack in mid-2026 and weighting business momentum, Anthropic is the trend line. That doesn't mean it's the right answer for your specific workload.
• Claude Code is the single product driving Anthropic's adoption — if you're not using it, that's the thing to evaluate first.
• Token-based pricing scales with use. Model your six-month spend before you commit to a stack, not after.
• The compute-constraint risk is real. Multi-provider fallback (Bedrock or Vertex AI) is now standard practice for anyone running Anthropic in production.
• Watch OpenAI's developer-product roadmap over the next two quarters. Their response will tell you whether this is a structural shift or a moment.

Further reading

• Ramp AI Index — May 2026 — primary source data
• Axios — Anthropic overtakes OpenAI in workplace AI adoption — straight news write-up
• VentureBeat — Anthropic finally beat OpenAI in business AI adoption, but 3 big threats — fragility analysis
• eWeek — Anthropic's Claude winning the enterprise AI race — enterprise framing
• Fortune — Anthropic deepens Wall Street push — adjacent context on the financial-services expansion