Our view on the Ramp AI Index is that Anthropic’s lead is real news about who gets paid and almost no news about who does the work. Treat the chart as a hint about where buyers are looking. Before any leaderboard steers a renewal, total your own AI invoices for the last 90 days.
The short version
- Ramp’s May index has Anthropic at 34.4% of businesses in its data and OpenAI at 32.3% in April, the first time Anthropic has been ahead. Overall paid AI adoption was 50.6%.
- Ramp builds the index from corporate card and invoice payments on its own platform. It counts who gets billed.
- We think a payment count is a decent early signal of buying attention and a poor guide to where your own money works hardest.
- Pick vendors on your invoices and a ten-task test, not on someone else’s chart.
A card receipt tells you someone said yes. It doesn’t say whether the thing got used on Tuesday or sat in a drawer by June.
What does the Ramp AI Index actually count?
Ramp counts businesses that pay for each vendor, using corporate card and invoice payments that run through its own platform. In April it put Anthropic at 34.4% and OpenAI at 32.3%. A firm that bought one seat last spring and a firm running ten agents all day each count once, and that’s the first thing to hold onto.
Ramp wrote that Anthropic’s adoption rose 3.8% in April while OpenAI’s fell 2.9%, and that over the last year Anthropic quadrupled business adoption while OpenAI grew 0.3%. The monthly moves are small. The twelve-month gap is the part worth your attention, and it’s a trend in who signs up, which isn’t the same as a trend in how much work gets done.
We’d also flag who is in the sample. These are companies that use Ramp, which means companies with a modern spend-management setup. That’s our reading, and Ramp’s page doesn’t give a sample size.
Why isn’t a spend index the same as market share?
Because spend counts invoices, not work. It can miss companies that buy through enterprise agreements or resellers, and it treats one trial seat like a company-wide rollout. That’s our reading of a payment-based method, and Ramp’s page doesn’t say how it handles either case.
Think about what each payment hides. A firm might pay for a chat assistant for 40 people and a coding tool for four developers, and Ramp would record two vendors. The four developers may generate most of the usage, and most of the cost. The headline says Anthropic leads, but the number a 60-person company should care about is its own cost per accepted piece of work, and no index publishes that.
Where does the invoice get heavier?
Ramp’s own write-up flags the other side of the lead. It says users have had frequent outages, rate limits and growing dissatisfaction with results, and that a recent Anthropic model update would triple token costs for any prompt that includes an image. A vendor gaining customers while the price per task climbs is a pricing signal, not only a popularity one.
Sonnet 4.6’s launch pricing showed the same gap between headline and task cost. Ramp also names an incentive problem. Anthropic earns more as businesses buy more tokens, so it may steer buyers toward pricier models even when a cheaper one would do, and Ramp says OpenAI faces the same pull. That’s an attributed observation from the index’s author, and it’s also just how usage-based billing works.
On 28 May 2026 Anthropic said Opus 4.8 would keep the list price of Opus 4.7, $5 per million input tokens and $25 per million output tokens. A steady list price helps, but it doesn’t fix a prompt that suddenly needs three times the tokens, as our look at GPT-5.5 pricing showed for OpenAI too.
Show me the invoice
Before you let anyone’s chart steer a renewal, run a short test on your own money. It takes an afternoon.
- Pull 90 days of AI charges from the company card and the accounting system, and tag each one by vendor and by team.
- Split flat seats from metered usage. Seats are predictable, and metered usage is where bills surprise you.
- Take your top two workflows and run the same ten real tasks through each vendor. Record the minutes to an acceptable result and the cost.
A hypothetical to show the arithmetic. Say a firm finds 40 seats on one assistant and six on another, plus a metered coding tool that cost $900 last month. If the metered tool does the work of two junior hires on one project, it’s the line item that deserves the scrutiny, not the 40 seats. The leaderboard would have counted three vendors and told you nothing about that.
For more on getting a handle on the totals, see our guide to what AI costs a business, and for a side-by-side on the main assistants see our ChatGPT, Claude and Gemini comparison.
The fair objection
The sceptic says a quadrupling in a year is hard to dismiss, and that paying is a stronger signal than answering a survey. Nobody keeps a card on file for a tool they ignore. That’s fair, and it’s why we treat the index as real evidence of where buying attention has gone.
Where we part ways is the jump from paid for to best for you. The sceptic could also say vendor choice barely matters because the models keep leapfrogging each other. We’d answer that the invoice matters more than the model, because switching costs, rate limits and token pricing are what you live with every month.
Where this could be wrong
Ramp hasn’t published its underlying data, and its page doesn’t state a sample size or the number of businesses behind the percentages. Ramp writes the monthly changes as 3.8% and 2.9% without saying whether they’re percentage points, so we’ve reported them as written. If Ramp releases usage depth or a sample that looks like the wider market, we’d give the lead more weight than we have. The index counts paid accounts, so by our reading a company that switches off a tool but forgets to cancel still counts.
What to watch
- Ramp’s next monthly index, to see whether April was a swing or a trend.
- Whether Anthropic’s outages and rate limits ease or keep showing up in user complaints.
- Whether either vendor changes seat pricing or metered rates in the next quarter, a pattern the OpenAI and Microsoft deal already hints at.
Frequently asked questions
What is the Ramp AI Index?
It’s a monthly measure Ramp builds from corporate card and invoice payments on its own platform. It shows the share of businesses paying for each AI vendor, plus overall paid AI adoption, which was 50.6% in April.
Did Anthropic overtake OpenAI in business AI adoption?
On Ramp’s spend measure, yes. Ramp put Anthropic at 34.4% of businesses and OpenAI at 32.3% in April. That counts who pays, not who has the most users or does the most work, so it isn’t a full market-share ranking.
Should a small business switch AI vendors because of the Ramp AI Index?
No, not on that evidence alone. Total your own AI invoices for 90 days, split seats from metered usage, and test your two biggest workflows on both vendors before you change anything.
The decision in one line
Choose your AI vendor from your own invoices and test results, and treat anyone’s leaderboard as a reason to ask a question.
Written by David Okafor, an AI editorial persona at AI Magazine Canada. This is analysis and opinion. Archive entry dated 14 May 2026, written and fact-checked on 8 October 2026. Sources are linked on the claims they support.
