How Ackman's Portfolio Concentration Reveals a High-Conviction Investment Thesis

Billionaire investor Bill Ackman has engineered one of the most concentrated stock portfolios among major hedge fund managers. With a net worth of $9.3 billion, Ackman ranks 311 on the Forbes World Billionaires List of 2025. According to investment analysts like Spencer Hakimian who track major institutional holdings, Ackman’s approach at Pershing Square Capital Management demonstrates how conviction-based investing can lead to outsized returns through selective positioning.

The hedge fund, which Ackman founded with an initial $54 million investment in 2004, now manages $19 billion in assets. What stands out most is the concentrated nature of his stock portfolio: 75% of the $15 billion equity position sits in just five companies. This isn’t accidental—it reflects a deliberate strategy rooted in identifying undervalued, high-quality businesses with strong cash generation and long-term competitive advantages.

The Network Effect Play: Uber Technologies at 19.6%

Ackman’s largest holding is Uber Technologies, representing 19.6% of the stock portfolio. He began accumulating shares in January 2025, building a 30.3 million share stake in the world’s largest ride-sharing and delivery platform. His rationale centers on several structural advantages: the powerful network effects embedded in the ride-share model, experienced management, robust operational execution, and the company’s ability to generate strong cash flows despite the capital-intensive nature of logistics.

Particularly interesting to analysts tracking this position is Ackman’s bullish view on autonomous vehicles. Rather than viewing self-driving technology as a threat to Uber’s traditional ride-share business, he sees it as an expansion opportunity—a way to further reduce costs and improve margins. The company’s capital-efficient model, combined with aggressive share buybacks that signal management confidence, supports his thesis that the market undervalues Uber’s earnings power. He projects annual earnings-per-share growth exceeding 30%, which should drive substantial stock appreciation over time.

The Asset Management and Infrastructure Pivot: Brookfield Corporation at 17.7%

Ackman’s second-largest position is Brookfield Corporation at 17.7% of the portfolio, added during 2024 when he identified significant value in the stock ahead of accelerating earnings growth. The position is complex: Brookfield Corporation owns 73% of Brookfield Asset Management, making it a proxy for one of the world’s largest alternative asset managers. Beyond that stake, the company operates Brookfield Wealth Solutions (BWS), an insurance and annuity business managing $135 billion in assets.

The full Brookfield ecosystem oversees more than $1 trillion in assets spanning infrastructure, renewable energy, real estate, and private equity. Two powerful tailwinds support Ackman’s thesis here. First, the explosive demand for artificial intelligence infrastructure has created a massive secular growth opportunity. Second, wealth management solutions driven by aging populations could potentially quadruple BWS’s asset base from $135 billion to $600 billion. The company targets 15% annual returns for shareholders long-term—a record it has beaten consistently over decades, including outperforming the S&P 500 by a substantial margin.

The Search and AI Dominance: Alphabet at 14.4%

Ackman began building his Alphabet position in 2023 and has incrementally added to it since. The Google parent company represents 14.4% of the current portfolio. His confidence rests on Google’s dominant 90% share of the search market, paired with aggressive AI integration across its platform ecosystem.

The integration extends across multiple revenue streams: AI-powered search results called AI Overviews, YouTube improvements, and rapid growth at Google Cloud. Recent quarterly results underscored the scale—Alphabet posted $100 billion in quarterly revenue for the first time with 33% year-over-year profit growth. Google Cloud’s $155 billion backlog signals robust future revenue visibility. Despite these metrics, Ackman believes the market has yet to properly value Alphabet’s AI transition and cloud computing momentum, presenting a valuation gap for long-term investors.

The Real Estate to Holding Company Transformation: Howard Hughes Holdings at 13.4%

Howard Hughes Holdings represents the most activist component of Ackman’s portfolio at 13.4%. He has been intimately involved with the company since its formation in 2010, and his involvement intensified recently. Earlier in 2025, Pershing Square acquired an additional 15% stake, raising the fund’s ownership to 47%. Ackman returned as executive chairman while bringing Pershing Square partner Ryan Israel aboard as chief investment officer.

His transformation thesis is ambitious: converting Howard Hughes from a traditional master-planned real estate company into a diversified holding company structure akin to Warren Buffett’s Berkshire Hathaway. The vehicle begins with acquiring property and casualty insurance businesses—self-funding operations capable of generating high returns on reinvested capital. By unlocking value trapped in the company’s vast real estate holdings while building a portfolio of compounding businesses, Ackman aims to materially grow intrinsic value per share. This represents a multi-year capital deployment opportunity.

The Franchise Business Model: Restaurant Brands at 10.6%

The final major holding, Restaurant Brands International, constitutes 10.6% of the portfolio. Ackman views the franchisor model as a capital-efficient template for generating recurring revenue and earnings growth. The company operates four iconic brands—Burger King, Tim Hortons, Popeyes, and Firehouse Subs—through a royalty and fee-based arrangement with franchisees.

The portfolio generates approximately 70% of earnings from international operations and the Tim Hortons Canada-U.S. business. To drive the next phase of growth, Restaurant Brands is investing heavily through 2028 in Burger King U.S. remodeling, digital technology, and marketing—a targeted effort to revive the domestic business while international and Tim Hortons segments expand through localized innovation and promotional strategies. Strengthening financials across the platform should unlock significant upside potential in the franchise model’s valuation multiple.

The Concentration Thesis: Quality Over Quantity

What Spencer Hakimian and other portfolio analysts emphasize about Ackman’s approach is the discipline required to concentrate 75% of assets into five holdings. This strategy works only when conviction is high, due diligence is thorough, and the businesses possess durable competitive advantages. Ackman’s portfolio reflects each of these characteristics—he owns companies with network effects, market dominance, pricing power, or structural cash generation capabilities.

The composition also reveals a sector-agnostic investment philosophy. Rather than overweighting a single industry, Ackman has diversified across transportation and logistics, asset management, advertising and cloud computing, real estate, and consumer franchising. Each position represents his assessment of an undervalued business capable of delivering compounding returns that justify the portfolio concentration risk.

For investors evaluating their own allocation strategies, Ackman’s portfolio offers a masterclass in high-conviction, high-quality value investing—the notion that owning fewer exceptional businesses often beats owning many average ones.