Billionaire investor Bill Ackman’s Pershing Square Capital Management disclosed on May 15, 2026, that it has been quietly building a significant new position in Microsoft Corporation [NASDAQ: MSFT] since February, as reported by Reuters. Ackman has been buying into the software giant during a period of share price weakness driven by investor concerns about the company’s $190 billion capital expenditure plan and its evolving relationship with OpenAI.

Microsoft shares have fallen more than 13% year to date, trading at approximately $409 according to Google Finance data, as investors questioned the return on investment from the company’s massive AI infrastructure spending programme and reassessed the implications of a restructured OpenAI partnership that no longer grants Microsoft exclusive rights to resell OpenAI technology through its Azure cloud platform.

Ackman explained in a lengthy Substack post published Thursday evening that Pershing Square began accumulating shares when Microsoft was trading at approximately 21 times forward earnings, a valuation he described as “broadly in line with the market multiple and well below Microsoft’s trading average over the last few years,” offering an unusual entry point for a company with the fundamental quality of Microsoft.

He argued that market participants are systematically underestimating the resilience of Microsoft 365, describing it as “tightly integrated into the daily workflow of nearly every large enterprise” in a way that makes it fundamentally different from standalone software products that could be displaced by better-performing AI alternatives over time.

The OpenAI restructuring, which has spooked some investors, was reframed by Ackman as a deliberate strategic pivot toward a more open, multi-model architecture rather than a concession, arguing that the new arrangement actually broadens Microsoft’s ability to offer AI capabilities from multiple providers through Azure rather than locking it into dependence on a single partner.

Ackman specifically highlighted that Microsoft’s 27% economic interest in OpenAI, valued at approximately $200 billion based on the startup’s most recent funding round, has not been meaningfully incorporated into the stock’s current market capitalisation, representing what he characterised as a significant embedded value that the market is effectively receiving for free at current prices.

Microsoft’s capital expenditure programme, which at $190 billion for 2026 is 61% above 2025 levels and approximately $35 billion above what Wall Street had been modelling before the earnings call disclosure, was defended by Ackman as a necessary J-curve investment in Azure infrastructure that will generate operating leverage over time rather than a permanent impairment of the company’s margin profile.

Evercore ISI chief technical analyst Rich Ross separately noted that Microsoft now has one of the “best acting charts” in the technology space, having reclaimed its 50-day moving average with authority and returned to a long-term support level that has held since the European financial crisis, giving Ackman’s fundamental thesis technical confirmation that the stock may have found a durable floor.

The Wall Street consensus on Microsoft remains overwhelmingly constructive, with 51 Buy ratings, zero Sell ratings, and a composite analyst price target of $561.56, implying more than 37% upside from current levels, suggesting that Ackman’s contrarian purchase is actually aligned with the direction of institutional analyst opinion even as the market’s sentiment has temporarily soured on the stock.