Group 1 - Berkshire Hathaway reduced its stake in Amazon by over 75% in Q4, while investing $351.7 million in the New York Times Company [1][3] - The company acquired 5.1 million shares of the New York Times Company, valued at $351.7 million at year-end [3] - Berkshire continued to trim its stakes in Bank of America and Apple, reducing them to 7.1% and 1.5%, respectively [4] Group 2 - Berkshire increased its stakes in Chevron and Chubb to 6.5% and 8.7%, respectively, during the same period [5] - Chubb's shares rose approximately 11% in Q4 after reports of an informal approach to acquire American International Group Inc. [5] - Warren Buffett has been active in making purchases, including a $9.7 billion deal for Occidental Petroleum Corp.'s petrochemical business and a $5.6 billion stake in Alphabet Inc. [6]