On May 15, Microsoft (MSFT) stock fell 0.42% to $422.07 after the Bill & Melinda Gates Foundation Trust sold its entire 7.7 million share MSFT stake, valued at $3.2 billion. The sale is part of a planned liquidity strategy: the foundation aims to increase annual grantmaking to $9 billion by 2026 and wind down its endowment by 2045. The holdings were built through direct donations from Bill Gates' personal wealth, not open-market purchases, and are subject to a 1.39% federal excise tax on gains. Separately, investor Bill Ackman's Pershing Square Capital Management disclosed a new 5.65 million share stake in Microsoft, worth nearly $2.3 billion. Ackman cited Microsoft's AI franchise as compelling at 21 times forward earnings, following the stock's dip after the OpenAI cloud shift. Despite Ackman's bullish move, net selling pressure from the foundation's exit weighed on the stock intraday. Microsoft remains a key S&P 500 driver, with tailwinds from the $9.7 billion IREN AI data center deal and a partnership with the London Stock Exchange. The recent dip raises questions about whether it's a buying opportunity or a warning ahead of the next earnings cycle.

Key facts

• Gates Foundation sold all 7.7M MSFT shares, worth $3.2B, for liquidity to fund grants.
• Bill Ackman's Pershing Square bought 5.65M MSFT shares, valued at $2.3B, citing AI valuation.
• Foundation holdings were from Bill Gates' personal donations, not open-market buys.
• MSFT fell 0.42% on the news; Ackman's bull case offset only part of selling pressure.
• Microsoft's AI deals (IREN, London Stock Exchange) provide long-term growth catalysts.