Regulatory filings show that last week, Berkshire Hathaway sold nearly 13 million of its Delta shares (for about $314 million) and about 2.3 million in Southwest shares (for about $74 million). This according to a recent CNBC article.

Berkshire—among the biggest shareholders of the four largest U.S. airlines, offered no reason for the sale but the article noted that they came “as the coronavirus pandemic drives the airline industry into perhaps its biggest crisis ever.” It added that last Friday, major U.S. airlines applied for payroll grants from the U.S. Treasury to keep workers employed and that Delta projected a drop in second-quarter revenue by 90%.