Microsoft books massive Anthropic windfall while OpenAI stake dips in latest quarter

Microsoft's fiscal 2026 earnings revealed an intriguing disparity in how its two competing AI investments performed. While the software giant recorded a substantial $3.2 billion gain from Anthropic in the latest quarter, its stake in OpenAI took a $600 million hit, painting a mixed picture of its portfolio.

The Anthropic windfall#

The Anthropic gain proved significant enough to warrant disclosure in Microsoft's investor materials. The $3.2 billion valuation jump boosted the company's diluted earnings per share by 33 cents for the quarter. This follows Microsoft's strategic commitment in November 2025, when it pledged $5 billion in capital alongside an agreement for Anthropic to purchase $30 billion in Azure services over time.

OpenAI's quarterly decline#

By contrast, Microsoft's OpenAI investment—in which the company holds roughly 27% ownership—saw its valuation reduced by approximately $600 million this quarter, trimming earnings per share by about 7 cents. The company accounts for this investment through mark-to-market accounting rather than disclosing specific revenue-sharing arrangements.

The bigger picture#

Though the quarterly OpenAI decline drew attention, the investment remains profitable when measured across the full fiscal year. Over the twelve-month period, Microsoft reported a $5 billion gain on OpenAI, adding $0.67 to annual earnings per share. Still, the remarkable speed at which Anthropic generated a gain nearly matching OpenAI's full-year benefit underscores how rapidly valuations in the AI sector are shifting. Microsoft's broader financial health—$331.8 billion in annual revenue and $133.7 billion in net income—renders these adjustments notable primarily for what they signal about the competitive landscape rather than their material impact on overall results.