Where Ackman and Tepper Agree (And Disagree) in Q1 2026

Two of the most closely watched hedge fund managers on Wall Street just revealed their Q1 2026 portfolios via SEC 13F filings. Bill Ackman's Pershing Square Capital Management and David Tepper's Appaloosa Management took some strikingly similar bets — but also made moves that put them on opposite sides of the same trade. Digging into the overlap and the divergence is one of the most useful exercises you can do with 13F data.

The Convergence: Amazon and Uber

When two elite investors independently pile into the same name in the same quarter, it's worth paying attention.

Both Ackman and Tepper significantly increased their Amazon exposure in Q1 2026. Ackman raised his Amazon stake from 9.61 million to 11.45 million shares, making it his second-largest position at roughly 17% of the portfolio. Tepper nearly doubled his Amazon position (+98%), making it his single largest holding.

The thesis is similar for both: Amazon Web Services continues to be a dominant force in enterprise cloud infrastructure, and the advertising business has emerged as a high-margin growth engine that the market may still be undervaluing relative to peers. Both investors appear to see Amazon less as a tech bet and more as a compounding business at a reasonable price.

Uber tells a parallel story. Tepper's Uber stake grew by a remarkable 242% in the quarter, while Ackman maintained it as his third-largest holding at roughly 16% of Pershing Square's book. Uber's pivot to profitability — with expanding free cash flow and a growing autonomous vehicle partnership ecosystem — appears to be the shared conviction. The stock has re-rated meaningfully over the past 18 months, yet both funds are doubling down rather than trimming.

You can explore how broadly Amazon and Uber appear across top portfolios using the InvestorLens overlap tool, which maps common holdings across dozens of institutional filers simultaneously.

The Divergence: Microsoft

This is where the two managers sharply part ways — and that divergence is arguably more interesting than the agreement.

Ackman initiated a brand new Microsoft position in Q1 2026, acquiring 5.65 million shares that immediately became his fourth-largest holding at around 15% of Pershing Square's portfolio. This is a high-conviction new entry into a name Ackman had previously avoided. The move signals his belief that Microsoft's AI monetization — through Copilot integrations across enterprise software and Azure's AI infrastructure buildout — justifies the valuation at current levels.

Tepper did the opposite. He meaningfully reduced his Microsoft exposure during the same quarter, trimming a position he had held. Tepper's playbook has leaned into mean-reversion and cyclicals in 2026 — he added aggressively to Micron, Taiwan Semiconductor, and Vistra Corp — suggesting he sees better risk/reward in names that haven't already re-rated for AI expectations.

Two brilliant investors, same quarter, opposite conclusions on the same stock. That's the kind of signal that demands your own research rather than blindly following either one.

Tepper's Macro Tilt

Beyond the individual stock moves, Tepper's Q1 2026 portfolio reveals a distinct macro posture. His biggest new buys — SanDisk, Vistra, Micron, and Taiwan Semiconductor — cluster around semiconductor supply, data center energy demand, and cyclical recovery. He exited airlines (American, Delta) entirely, closing out what was apparently a post-COVID reopening thesis that has now run its course.

This kind of top-down positioning read is exactly what 13F data is good for. The InvestorLens macro consensus page aggregates positioning signals across dozens of top funds to surface where the institutional smart money is leaning as a group — useful context for any of these individual bets.

Ackman's Concentration Play

Pershing Square's portfolio remains extraordinarily concentrated. The top five holdings — Brookfield, Amazon, Uber, Microsoft, and Restaurant Brands International — make up roughly 78% of the fund. Ackman simultaneously exited his Hilton position entirely and trimmed Alphabet, Meta, and Brookfield to fund the Microsoft entry.

This is a portfolio that requires enormous conviction in each name. Ackman has long argued that concentration is a feature, not a bug — that truly understanding six to eight businesses is better than tracking fifty. Q1 2026 is a clean example of that philosophy in action: out with Hilton (thesis complete), in with Microsoft (new long-duration AI thesis).

How to Use This Data

The most dangerous way to read 13F filings is as a buy list. These filings are published 45 days after quarter-end, meaning the data you're reading today reflects positions as of March 31. Positions may have already changed. More importantly, what's right for a $14 billion concentrated fund may be entirely wrong for your personal portfolio.

The right use is as a starting point for research. When you see two seasoned investors agreeing on Amazon and Uber, ask why — and then do your own work to pressure-test the thesis. When you see them disagreeing sharply on Microsoft, that's an invitation to understand both sides of the argument before forming a view.

Browse current holdings for Pershing Square and hundreds of other institutional filers on InvestorLens, and use the flow tracker to see which names are seeing the most institutional accumulation across the board right now.

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Data sourced from public SEC 13F filings. Educational research only — not investment advice.