When your biggest investor is also your biggest supplier and one of your largest customers, the accounting gets interesting. OpenAI’s confidential S-1 filing, submitted to the SEC on June 8, reveals just how tangled those relationships have become.
In the first quarter of 2026, approximately 45% of OpenAI’s total expenses were attributed to related parties. A full 72% of OpenAI’s cost of revenue in Q1 went to Microsoft and other hyperscalers.
Microsoft owns approximately 27% of OpenAI, a stake valued at around $135B after the company’s recapitalization. Microsoft has invested a total of $13B into OpenAI, with $11.6B already deployed by late 2025. It’s also the primary provider of Azure cloud infrastructure that OpenAI runs on, and revenue-sharing agreements have historically funneled a portion of OpenAI’s earnings back to Redmond.
The related-party revenue side of the equation is growing even faster. OpenAI pulled in $758M in related-party revenue during Q1, a twelve-fold increase year-over-year.
OpenAI also made $488M in non-cash equity payments for compute services during the quarter.
