On Dec. 13, this rumor became reality when Amgen (NASDAQ: AMGN) paid a whopping $27.8 billion for the drugmaker. A perfect storm of rampant inflation, global supply chain kinks, rising interest rates, geopolitical unrest, a wave of profit-taking following a strong 2021, and the ongoing effects of COVID-19 pushed every major U.S. stock index into bear territory last year. Berkshire first initiated a position in the global entertainment giant in the first quarter of 2022, according to the diversified holding company's 13F filings with the U.S. Securities and Exchange Commission.