OpenAI memo says Microsoft partnership limited its ability to work with other cloud providers

OpenAI's chief revenue officer told staff that the company's longstanding partnership with Microsoft $MSFT had constrained its ability to serve enterprise customers on competing cloud platforms, according to a memo viewed by CNBC.

"Our Microsoft partnership has been foundational to our success. But it has also limited our ability to meet enterprises where they are — for many that's Bedrock," Denise Dresser wrote in the Sunday memo, referring to Bedrock, a platform run by Amazon $AMZN Web Services through which businesses can access a range of leading AI models. Dresser added that customer demand since the Amazon partnership was announced in late February has been "frankly staggering."

Dresser, who joined OpenAI as CRO in December, told CNBC earlier this month that enterprise customers make up 40% of the company's revenue and are expected to match its consumer business by the end of the year.

A renegotiated agreement reached in October 2025 addressed the limits Dresser described, with OpenAI gaining the ability to co-develop products alongside third parties and Microsoft relinquishing its right of first refusal over compute resources. As part of that revised arrangement, OpenAI agreed to spend an additional $250 billion on Microsoft's Azure cloud, according to Geekwire.

Amazon announced it plans to invest up to $50 billion in OpenAI as part of a strategic partnership. In addition to the equity stake, an existing AWS cloud contract worth $38 billion was extended by $100 billion over eight years. OpenAI also agreed to use two gigawatts of power through AWS infrastructure running on Trainium, Amazon's proprietary AI chip, according to Geekwire.

Despite the new arrangement, Microsoft retains meaningful positions under the revised partnership. Under the revised terms, stateless OpenAI API traffic continues to flow exclusively through Azure, and Microsoft retains sole licensing rights to OpenAI's underlying intellectual property — the technology behind its Copilot assistant, Bing search integration, and the Azure OpenAI Service. In a joint statement, Microsoft said it welcomed the deal, noting that arrangements of this kind had been anticipated all along under the terms of its existing agreements. Microsoft did not respond to CNBC's request for comment on Dresser's memo.

Tensions have increasingly surfaced in the OpenAI-Microsoft relationship, with each company encroaching on territory the other considers its own. By mid-2024, Microsoft had begun listing OpenAI as a competitor in regulatory filings, even as it continued building out its own AI models and chip capabilities. OpenAI, meanwhile, has turned to cloud providers including Google $GOOGL and Oracle $ORCL for additional capacity.

In the memo, Dresser also addressed competition with Anthropic, saying its rival's strategy is built on "fear, restriction, and the idea that a small group of elites should control AI." She added that Anthropic made a "strategic misstep to not acquire enough compute." Anthropic did not respond to CNBC's request for comment.