Companies using credits bundled with Microsoft for Startups have found some unwelcome surprises on their credit card statements after deploying Anthropic’s Claude via Azure AI Foundry.
A Register reader told us he tested the LLM via Microsoft’s platform using Startup Credits, however, this ended with credit card charges. Microsoft and Anthropic then each directed our reader to contact the other company in order to get a resolution.
Takuya Tominaga, founder and CEO of Leach, a generative AI startup based in Tokyo, discovered the unexpected bill following some experimentation with Claude. The problem is that Microsoft’s documentation conflicts with what a moderator on one of the company’s forums wrote about how credits are used.
Moderator on Microsoft forums writes about the deployment of Claude Opus 4.5 on Azure AI Foundry – Wayback Machine answer, screenshot taken on January 13
Referring to the deployment of Claude Opus 4.5 on Azure AI Foundry, the moderator wrote: “Startup credits (Azure Sponsorship) apply to these charges until the credit balance is exhausted. After that, standard pay‑as‑you‑go rates kick in.”
The post was later amended to say: “Startup credits don’t apply. It is only available for enterprise and MCA-E subscriptions.”
Moderator on Microsoft forums writes about the deployment of Claude Opus 4.5 on Azure AI Foundry – current, edited answer
The edit is in line with Microsoft’s documentation, which contains the clause: “Startup credits cannot be used for Microsoft Azure support plans, third-party branded products, products sold through Microsoft Azure Marketplace, or products otherwise sold separately from Microsoft Azure.”
Microsoft grants fledgling businesses up to $150,000 of Azure credits as part of Azure Credits for Start-ups.
However, according to Tominaga, “the UI makes no distinction between credit-covered and Marketplace-billed models,” meaning that the first time he was aware of the situation was when he saw an entry on his credit card statement totaling approximately $1,600.
Tominaga is not alone. The Register has seen evidence of other charges made to startups by Microsoft, including one to the tune of approximately $3,000, while their Startup Credits remained unused.
Still, while this may have been an honest mistake by the start-ups, a moderator on a Microsoft forum making inaccurate claims (before the post was edited) about the applicability of Startup Credits is unhelpful.
To date, Tominaga has struggled to get the charge refunded. He told us: “Microsoft says ‘contact Anthropic for a refund.’ Anthropic says ‘We have no visibility into Azure billing – contact Microsoft.’ Both confirmed in writing. Nobody is accountable.”
The Register asked Microsoft to comment. A spokesperson sent us a statement:
“We listen closely to customer feedback and are continuously working to provide clear guidance in our product documentation, including pricing details and credit eligibility. We encourage customers to rely on official documentation and to submit a support ticket for additional assistance specific to their environment.”
Anthropic did not respond to our request for comment.
Tominaga’s experience is a cautionary tale about reading the fine print in Microsoft for Startups’ terms and conditions, and treating advice from Microsoft support forum posters, including those badged as “Microsoft External Staff • Moderator” (typically a contractor, not employees) with some skepticism.
It is also a warning for Microsoft that faith in its products and pronouncements can all too easily – and expensively – be undermined by an error in a post and some unexpected credit card charges resulting in a surprise bill. ®