Fortune: Who is investing in Microsoft?

Investing Microsoft

Bill Ackman has been quietly buying Microsoft since February, when AI fears were dragging the stock

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Eva Roytburg

Fellow, News

May 15, 2026, 11:14 AM ET

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US hedge fund manager Bill Ackman, CEO of Pershing Square Capital Management, speaks during the 29th annual Milken Institute Global Conference at the Beverly Hilton in Beverly Hills, California on May 4, 2026.

US hedge fund manager Bill Ackman, CEO of Pershing Square Capital Management, speaks during the 29th annual Milken Institute Global Conference at the Beverly Hilton in Beverly Hills, California on May 4, 2026.Patrick T. Fallon / AFP via Getty Images

Bill Ackman is going against the grain to back Microsoft.

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Pershing Square Capital Management, the hedge fund run by the billionaire investor, has built a new position in the software giant. 

And in typical Ackman fashion, he disclosed the stake in his trademark style: a lengthy post on X on Friday ahead of his firm’s quarterly 13F filing (a required filing for institutional investment managers with over $100 million in assets). He did not disclose the size, but called it a “core holding.”

Pershing started accumulating shares in February, after Microsoft’s stock fell about 10% the day after Q2 earnings, with a 1% lower-than-expected cloud growth alongside a surge in capital spending. “We were able to establish our position at a valuation of 21 times forward earnings, broadly in line with the market multiple and well below Microsoft’s trading average over the last few years,” Ackman wrote in the post.

Microsoft’s stock is down more than 15% year-to-date as it fights to prove that its Azure cloud business has enough revenue to justify its AI spending. The erosion of its partnership with AI, which was recently restructured to strip Microsoft of exclusive distribution rights, only furthered those concerns.

Ackman sees that restructuring as a pivot to a multi-model architecture that can better suit the needs of its enterprise customers.

  • He also argues that investors underestimate Microsoft’s 365 productivity suite and its stickiness, saying the suite is “deeply embedded” in enterprises and “nearly impossible to replicate,” he wrote.

Ackman pushed back on concerns over Microsoft’s $190 billion 2026 capex budget, arguing it as growth investment on a J curve rather than a threat to margins. He also pointed out that Microsoft’s market capitalization does not yet reflect its 27% economic interest in OpenAI— worth approximately $200 billion at the startup’s most recent funding round valuation, he said.

The Microsoft buy continues Ackman’s pattern of stepping into Big Tech during periods of AI-related skepticism.

“We acquired Alphabet when the stock declined substantially on the release of ChatGPT in late 2022, Amazon in the weeks following Liberation Day, and Meta more recently on the market’s response to the company’s unexpectedly large capex guidance,” he wrote.

The Fortune 500 Innovation Forum will convene Fortune 500 executives, U.S. policy officials, top founders, and thought leaders to help define what’s next for the American economy, Nov. 16-17 in Detroit. Apply here.

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By Eva RoytburgFellow, News

Eva covers macroeconomics, market-moving news, and the forces shaping the global economy.

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About michelleclarke2015

Life event that changes all: Horse riding accident in Zimbabwe in 1993, a fractured skull et al including bipolar anxiety, chronic fatigue …. co-morbidities (Nietzche 'He who has the reason why can deal with any how' details my health history from 1993 to date). 17th 2017 August operation for breast cancer (no indications just an appointment came from BreastCheck through the Post). Trinity College Dublin Business Economics and Social Studies (but no degree) 1997-2003; UCD 1997/1998 night classes) essays, projects, writings. Trinity Horizon Programme 1997/98 (Centre for Women Studies Trinity College Dublin/St. Patrick's Foundation (Professor McKeon) EU Horizon funded: research study of 15 women (I was one of this group and it became the cornerstone of my journey to now 2017) over 9 mth period diagnosed with depression and their reintegration into society, with special emphasis on work, arts, further education; Notes from time at Trinity Horizon Project 1997/98; Articles written for Irishhealth.com 2003/2004; St Patricks Foundation monthly lecture notes for a specific period in time; Selection of Poetry including poems written by people I know; Quotations 1998-2017; other writings mainly with theme of social justice under the heading Citizen Journalism Ireland. Letters written to friends about life in Zimbabwe; Family history including Michael Comyn KC, my grandfather, my grandmother's family, the O'Donnellan ffrench Blake-Forsters; Moral wrong: An acrimonious divorce but the real injustice was the Catholic Church granting an annulment – you can read it and make your own judgment, I have mine. Topics I have written about include annual Brain Awareness week, Mashonaland Irish Associataion in Zimbabwe, Suicide (a life sentence to those left behind); Nostalgia: Tara Hill, Co. Meath.
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