Billionaire Bill Ackman's Billion-Dollar Bet on Amazon Isn't His Largest Position -- This One Is

When billionaire investor Bill Ackman makes a move, Wall Street pays attention. The founder of Pershing Square has built his reputation on high-conviction, concentrated bets -- often holding fewer than a dozen stocks in his portfolio. That approach has produced outsized returns over time.

Lately, Ackman surprised many by revealing a massive billion-dollar stake in Amazon. For a longtime critic of big tech valuations, the move raised eyebrows. But what's more interesting is that Amazon isn't even Ackman's biggest position today. That honor goes to Uber Technologies (UBER 1.27%).

So, what does this say about how Ackman invests? And what lessons can individual investors take away? Let's break it down.

Ackman's portfolio: Amazon is significant -- but not the largest

Pershing Square bought 5.82 million Amazon shares, worth about $1.3 billion as of this writing, making Amazon roughly 9% of its U.S. equity portfolio -- a significant stake, but not the largest. Uber makes up about 21% of his fund at $2.8 billion, making it his top holding.

Ackman didn't abandon high-conviction positions, but added Amazon to a portfolio that already featured Uber, Brookfield Corporation, and Restaurant Brands. That's a calculated addition, not a replacement.

Uber: Ackman's deepest bet -- and why it matters.

So why does Ackman like Uber that much? In his own words:

We believe that Uber is one of the best-managed and highest-quality businesses in the world. Remarkably, it can still be purchased at a massive discount to its intrinsic value. This favorable combination of attributes is extremely rare, particularly for a large-cap company.

In short, Ackman viewed Uber as an opportunity to invest in a high-quality, well-managed business at a cheap valuation. And that says a lot about Uber. Led by Dara Khosrowshahi (previously the CEO of Expedia), Uber has transitioned from a cash-burning disruptor into a disciplined operator with a wide moat in mobility and delivery. Uber now serves 180 million users per quarter across mobility and delivery.

The strength of Uber's model lies in its network effects -- riders attract drivers, drivers attract riders, and the same flywheel holds for merchants and consumers in food delivery. That scale makes it increasingly difficult for competitors to chip away at its position.

And the company's growth runway is far from tapped out. Beyond mobility and delivery, Uber is building new verticals in advertising and autonomous rides, both of which could become meaningful profit centers over time.

Uber may not have Amazon's scale, but it has something Ackman values deeply: the potential for asymmetric upside as the market continues to underestimate its long-term cash generation power.

What does this say about Ackman's investing strategy?

Ackman continues to run a concentrated portfolio built around conviction, not headlines. His approach layers durable core holdings like Uber with opportunistic new stakes such as Amazon. He times his entries with discipline -- stepping into Amazon when tariff-driven weakness dragged the stock down, and doubling down on Uber after its 2024 stumble.

Just as important, he sizes his bets according to conviction. Uber holds a top position, significantly larger than Amazon, indicating where Ackman sees the greatest multi-year upside. This isn't fast-money trading. It's deliberate positioning around businesses Ackman believes can compound value for years, backed by fundamentals rather than market noise.

So what does it mean for investors?

Ackman might have captured the spotlight with his holdings in Uber and Amazon. But investors shouldn't just mirror his trades. Instead, the lesson lies in how he invests:

• Buy high-quality companies facing temporary challenges.
• Scale positions to your conviction and risk tolerance.
• Think in decades, not quarters -- long runways take years to play out.

In short, Ackman's moves remind us that elephants can still dance. Uber and Amazon are both massive companies, yet size hasn't stopped them from compounding value. For long-term investors, the real opportunity lies in spotting those durable businesses, tracking them closely, and acting when the price -- and conviction -- line up.