48% of Billionaire Bill Ackman's Portfolio Is Invested in 3 AI Stocks, One of Which Is Expected to See Its Addressable Market 10X by 2033

No investment trend has been hotter on Wall Street over the last three years than artificial intelligence (AI). Giving software and systems the capacity to make accurate, split-second decisions without human intervention represents a technological leap forward that can benefit most industries around the globe.

This is a multitrillion-dollar opportunity that isn't lost on Wall Street's most successful investors. Based on quarterly Form 13F filings with the Securities and Exchange Commission, several well-known billionaire money managers have piled into an assortment of promising AI stocks, including Pershing Square Capital Management's boss, Bill Ackman.

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Ackman is best known as an activist investor who identifies undervalued assets and often pushes for corporate change or board seats to unlock shareholder value. His fund closed out the third quarter with $14.6 billion in assets under management, spread across 11 holdings. Portfolio concentration is a relatively common trait among activist investors.

But what's noteworthy about Ackman's investment portfolio is his favoritism of artificial intelligence stocks. Approximately 48% of Pershing Square Capital Management's invested assets can be traced back to just three brand-name AI stocks -- one of which is at the forefront of an exceptionally fast-growing addressable market.

Alphabet: 19% of invested assets

Perhaps it's no surprise that the favorite artificial intelligence stock of billionaires, Alphabet (NASDAQ: GOOGL)(NASDAQ: GOOG), is one of Bill Ackman's largest holdings. As of Sept. 30, Pershing Square held 4,843,973 shares of Alphabet's Class A shares (GOOGL) and 6,342,031 of its Class C shares (GOOG). Collectively, 19% of the roughly $14.6 billion Ackman was overseeing at the end of the third quarter was tied to this member of the "Magnificent Seven."

Alphabet's AI connection primarily has to do with its incorporation of generative AI solutions and large language model capabilities into its cloud infrastructure service platform, Google Cloud. These solutions are accelerating the sales growth rate of this high-margin operating segment for Alphabet -- 47% year-over-year sales growth in the December-ended quarter.

However, Alphabet's foundational advertising-driven segments have been the catalyst for its aggressive investments in AI. Google is the world's leading internet search engine, while Alphabet-owned streaming service YouTube is the second-most-visited social destination on the planet. Google and YouTube make Alphabet a logical destination for advertisers looking to target their message(s), leading to strong ad pricing power and abundant cash flow.

Alphabet is also sitting on a hearty treasure chest of capital. It ended 2025 with $126.8 billion in combined cash, cash equivalents, and marketable securities, and is averaging more than $40 billion per quarter in cash generated from operating activities. Alphabet can pay a dividend, buy back its stock, reinvest in its core operations, and aggressively spend on next-big-thing trends, such as AI, and still have plenty of cash left over.

Image source: Amazon.

Amazon: 8.7% of invested assets

Another trillion-dollar member of the Magnificent Seven that's a core holding for billionaire Bill Ackman at Pershing Square Capital Management is e-commerce colossus Amazon (NASDAQ: AMZN). The 5,823,316 shares held by Pershing Square comprised 8.7% of invested assets as of Sept. 30.

Although most consumers familiarize themselves with Amazon through its world-leading online marketplace, it's Amazon Web Services (AWS) that generates a majority of the company's operating income.

Whereas Google Cloud is the world's No. 3 cloud infrastructure service platform by total spend, AWS is No. 1 and accounts for close to a third of estimated cloud infrastructure spending. Amazon has been aggressively leaning on AI solutions within AWS to support its clients and boost its already impressive growth rate. Similar to Google Cloud, AWS's growth rate has been reaccelerating, with 24% constant-currency sales growth during the fourth quarter.

But Amazon has other ancillary operations that produce impressive margins. Its growing content library, featuring exclusive rights to Thursday Night Football and select NBA games, has made its Prime subscription service a moneymaker. Likewise, billions of monthly visitors to its online marketplace, coupled with its aforementioned exclusive content, are decisively boosting its advertising services segment.

Amazon ended 2025 with around $123 billion in combined cash, cash equivalents, and marketable securities, meaning it has more than enough capital to invest in high-growth initiatives.

Uber Technologies: 20% of invested assets

However, billionaire Bill Ackman's biggest AI wager of them all is domestic ride-share leader Uber Technologies (NYSE: UBER). Pershing Square Capital Management's third-quarter 13F shows Ackman closed out September with a 30,270,518-share stake in Uber, representing approximately 20% of invested assets.

Ride-sharing is a global addressable opportunity expected to grow 10X, from less than $88 billion in 2025 to $918 billion by 2033, according to a report by Straits Research. Uber finds itself at the forefront of this rapidly growing service, with AutoInsurance.com pegging its share of the U.S. market at 76% in March 2024.

What investors may not realize is that Uber's ride-share platform relies on AI for its success. Artificial intelligence is responsible for route tracking, dynamic pricing models, and the pairing of drivers with riders. Ongoing investments in AI are needed to ensure Uber's ride-sharing operations remain a cash cow.

But Uber is much more than just a ride-sharing company. It's the parent of food delivery service Uber Eats and a freight logistics company. These segments, which also incorporate AI as a foundational tool, are linked at the hip to the health of the U.S. economy. Given that economic cycles aren't linear, long periods of economic expansion allow Uber's ancillary operating segments to expand over time.

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