Question: In January 2016  Precision Castparts Corp. became a sibsidiary of a multinational conglomerate holding company headquartered where?
Sentence (from "Berkshire Hathaway"): Since 2016, the company has acquired large holdings in the major US airline carriers and is currently the largest shareholder in United Airlines and Delta Air Lines and a top 3 shareholder in Southwest Airlines and American Airlines.
Relevant evidence: No