Billionaire Bill Ackman Has 13% of Pershing Square Capital Management's $19 Billion Hedge Fund in 1 Stock That's 31% Below Its 52-Week High

Bill Ackman's investment approach is to own high-quality businesses for the long haul. The hedge fund firm he founded more than two decades ago, called Pershing Square Capital Management, deploys this strategy with a concentrated portfolio. Retail investors can follow closely to find potential buying opportunities. In January 2025, the billionaire investor started building a stake in a disruptive business. This growth stock now represents 12.7% of the entire $19 billion portfolio, making it the single largest holding. Ackman is sticking to his conviction, even though shares trade 31% below their 52-week high (as of Sept. 17). Missed AI's "Act 1"? Act 2 Could Be 15x Bigger.