Ackman had almost 25% of his firm's net assets in one of these stocks at the end of 2023.Bill Ackman is one of the most widely followed billionaire investment managers, with 1.2 million followers on X. His following is based on a successful career as a rising star on Wall Street in the 1990s before starting his current firm Pershing Square Capital Management in 2004. Ackman's net worth is currently estimated at more than $4 billion, according to Forbes.Pershing Square Capital Management makes long-term inve ...