Yahoo Finance·2026-02-27 19:36Core Insights - Bill Ackman, a billionaire investor and CEO of Pershing Square Capital Management, is known for his value investing approach, focusing on a concentrated portfolio across various industries [1] Group 1: Investment Activities - In early 2023, Pershing Square initiated a position in Alphabet by acquiring 2.2 million Class A shares and 8.1 million Class C shares [2] - In the fourth quarter, Pershing Square reduced its Class A position in Alphabet by 86% and trimmed its Class C holding by 2% [3] - Ackman doubled down on Amazon by adding 3.8 million shares to Pershing Square's position during the fourth quarter, following an initial purchase of 5.8 million shares in the second quarter [5][6] Group 2: AI Ecosystem and Market Position - Both Amazon and Alphabet are building vertically integrated AI ecosystems, with Amazon Web Services (AWS) holding a 28% market share in cloud infrastructure, while Alphabet's Google Cloud has a 14% share [7] - Amazon is designing proprietary chips, such as Trainium and Inferentia, to reduce dependence on Nvidia's architectures, similar to Alphabet's custom silicon work with Broadcom [8]