44% of Billionaire Bill Ackman's Portfolio at Pershing Square Is Concentrated in Just 4 AI Stocks |

Few events are more telling or exciting for the investing community than the quarterly filing of Form 13Fs with regulators. A 13F provides a concise snapshot of which stocks Wall Street’s sharpest money managers, such as Pershing Square‘s billionaire boss, Bill Ackman, purchased and sold in the latest quarter.

But what really stands out about Ackman’s portfolio is its concentration. While Ackman has always been a fan of consolidating his fund’s capital into his best ideas, a substantial portion of those ideas are related to artificial intelligence (AI). As of the June-ended quarter, Uber Technologies (UBER +2.43%), Microsoft (MSFT +1.68%), Amazon (AMZN +3.97%), and Meta Platforms (META +1.21%) comprised 44.4% of Pershing Square’s $19.5 billion investment portfolio.

Pershing Square’s billionaire boss is focusing on AI applications pioneers

Most billionaires can’t seem to get enough of the hardware companies facilitating the AI infrastructure build-out for hyperscalers. However, Ackman is focusing his efforts on AI applications pioneers, and there are likely a couple of good reasons for this decision.

To begin with, history shows that every game-changing innovation for more than 30 years has experienced an early innings bubble-bursting event. If investors, yet again, overestimate the pace of adoption and/or optimization of Wall Street’s hottest technology, AI infrastructure stocks would likely be hit hardest.

— Geiger Capital (@Geiger_Capital) May 8, 2026

In comparison, companies deploying or integrating AI solutions atop their foundational platforms wouldn’t endure anywhere near the same level of disruption if the AI bubble were to burst. For instance, cloud services for Microsoft and Amazon should continue to grow unfazed, while Meta’s social media platforms would remain premier targets for advertisers.

Additionally, all four of these businesses possess sustainable moats:

• Uber Technologies accounts for around three-quarters of the U.S. ride-share market, with AI used to match drivers to riders and dynamically price the company’s services.
• Microsoft’s Azure is the world’s No. 2 cloud infrastructure services platform, while Windows remains the leading desktop operating system.
• Amazon is the undisputed global leader in online retail sales and is also the company behind the world’s No. 1 cloud infrastructure services platform, Amazon Web Services.
• Meta attracted an average of 3.6 billion people to its family of apps each day in June, demonstrating the lure of its social media platforms.

These moats ensure sustainable market share and generally robust operating cash flow.

Most importantly, AI applications stocks are fundamentally attractive amid a historically pricey stock market. As of the closing bell on Aug. 21, the forward price-to-earnings (P/E) ratios for this quartet are as follows:

• Uber: 17
• Microsoft: 20.5
• Amazon: 24.7
• Meta: 16.2

Although Amazon’s forward P/E might appear a bit pricey relative to the others, the company is trading at a historically low forward price-to-cash-flow ratio. Given that Amazon reinvests a huge chunk of its operating cash flow into its fastest-growing operations, cash flow is a potentially better metric for valuing the company.

While most billionaires have focused on AI infrastructure stocks, billionaire Bill Ackman is betting the proverbial farm on AI applications transforming the world.

Sean Williams has positions in Amazon and Meta Platforms. The Motley Fool has positions in and recommends Amazon, Meta Platforms, and Microsoft. The Motley Fool recommends Uber Technologies. The Motley Fool has a disclosure policy.