Microsoft’s fiscal fourth-quarter earnings, reported July 29, contained an accounting curiosity: a single quarter of gains from one AI investment nearly equaled a full year of returns from the other. The company recorded a $3.2 billion gain on its stake in Anthropic, adding 33 cents to diluted earnings per share of $4.81, while its much larger position in OpenAI contributed roughly $480 million net to quarterly net income, about 7 cents a share, according to the company’s own reconciliation.
The contrast is starker over the full fiscal year that ended June 30. Microsoft’s OpenAI investment generated about $5 billion in gains for the year, contributing 67 cents to earnings per share. The Anthropic stake matched a large share of that total in three months alone. Microsoft said the disparity was significant enough that it chose to disclose the Anthropic gain explicitly in its earnings materials, even though it does not routinely revalue the investment.
The structure behind the numbers
The Anthropic gain traces back to November 2025, when Microsoft invested $5 billion in the AI lab as part of a circular arrangement: Anthropic in turn committed to buying $30 billion worth of Azure cloud services. The structure means the gain reflects not just the rising value of the equity stake but the cloud revenue the investment was designed to lock in. Because Microsoft does not mark the Anthropic position to market every quarter, the $3.2 billion figure is best read as a periodic snapshot rather than a regular line item.
OpenAI is a different accounting animal. Microsoft owns roughly 27 percent of the company and updates the value of that stake quarterly, though it does not disclose the revenue-share payments OpenAI makes under their arrangement. TechCrunch reported the OpenAI stake was marked down by roughly $600 million during the quarter, a decline the company’s net accounting more than offset with other OpenAI-related income. Either way, the direction is clear: OpenAI’s quarterly contribution was a small fraction of Anthropic’s, and the two bets are pulling in opposite directions on Microsoft’s income statement.
The rest of the quarter
The investment swings were discrete items on top of a strong quarter. Revenue reached $90 billion, up 18 percent year over year, with net income of $35.8 billion, up 31 percent. Azure and other cloud services revenue grew 43 percent, and Microsoft Cloud revenue as a whole hit $59.3 billion, up 27 percent. For the full fiscal year, revenue totaled $331.8 billion with net income of $133.7 billion and diluted earnings per share of $17.95. Microsoft said Azure revenue surpassed $100 billion annually for the first time, and commercial remaining performance obligations grew 84 percent to $678 billion, a backlog that reflects the multi-year commitments underpinning its AI infrastructure spending.
Microsoft’s results also included a net benefit from lower-than-expected costs tied to its voluntary retirement program, partially offset by severance and impairment charges in its Xbox business.
What the divergence signals
The two stakes sit on opposite sides of Microsoft’s AI strategy. OpenAI remains its closest partner and the anchor of its consumer AI ambitions, while Anthropic has become a strategic counterweight, buying Azure capacity at a scale that makes it one of the cloud division’s largest AI customers. The accounting asymmetry, with OpenAI marked quarterly and Anthropic marked occasionally, means investors only see the full shape of both positions at moments like this earnings report.
The headline takeaway is less about which lab is winning and more about how Microsoft has structured itself to benefit from both. When two leading AI developers are both paying Microsoft for compute, and one of those relationships also produces a multibillion-dollar paper gain, the company’s position as the toll road of the AI boom looks increasingly deliberate.
Sources: Microsoft logs $3.2B from Anthropic investment, but OpenAI was a mixed bag (TechCrunch, July 29); Microsoft FY26 Q4 earnings release (Microsoft Investor Relations, July 29); Microsoft (MSFT) Q4 earnings report 2026 (CNBC, July 29); Microsoft books Anthropic gain as OpenAI stake marks mixed fiscal 2026 results (Traders Union, July 30)