One customer, a tenth of the till: Microsoft's filing reads the OpenAI line aloud

The press release tells you what a company wants you to hear. The quarterly report tells you what the accountants require it to say. Microsoft’s 10-Q for the three months to September, filed on Wednesday evening, contains one sentence worth reading slowly: because OpenAI is a related party, Microsoft must disclose what it earns from it. The answer is $10.0 billion of revenue in the quarter, “inclusive of revenue-sharing payments”¹.

Set that against the whole. Total revenue was $92.3 billion¹. Desk arithmetic: OpenAI arrangements were about 10.8% of everything Microsoft sold, roughly one dollar in nine. For the whole of the previous financial year the figure was $24.1 billion, TechCrunch notes, so the latest quarter alone ran at well over a third of that². The filing also shows what has not yet arrived: accounts receivable from OpenAI stood at $7.2 billion at the end of September, against $6.0 billion at the end of June¹. That is money owed for work already done, not extra revenue². Microsoft’s stake has slipped to about 24% on an as-converted basis¹, from about 25% in June, according to TechCrunch².

The second thing the filing shows is the building bill. Additions to property and equipment were $39.4 billion, against $19.4 billion a year earlier¹. Desk arithmetic: just over twice as much. Leases that have been signed but have not yet started, mostly for data centres, add up to $364.6 billion, to begin between fiscal 2027 and 2034¹. That is a very large promise, written into a footnote.

Here the comparison with this week’s other filings is instructive. Operations brought in $58.0 billion of cash¹. Desk arithmetic: after capital spending, $18.6 billion was left, down from about $25.7 billion a year earlier but still positive. Microsoft is building hard, but this quarter it collected fast enough to pay for it; Alphabet, by its own filing, did not, with free cash flow of minus $9.1 billion⁴. Commercial contracts already signed but not yet delivered reached $677 billion, up 73%, and the company expects to recognise about 30% of that over the next twelve months¹.

One more line belongs on the payroll page. Operating expenses rose 6%, and “total company headcount decreased 2%”¹. A company can double its spending on machines while employing slightly fewer people; the filing says so plainly, without a slogan in either direction.

The lesson for you is a small one. When a partnership is described in keynotes as a vision, look for the related-party note. It is where the vision becomes invoices, receivables and dates. Nothing here is investment advice.