Warren Buffett’s Berkshire Hathaway Inc. boosted its stake in Delta Air Lines Inc. last week, taking advantage of bargain prices amid market declines.

Berkshire acquired more than 976,000 shares for about $45.3 million, or an average price of $46.40, according to a filing Monday. Delta stock dropped about 20% last week as markets plummeted on concern about the coronavirus.

Buffett, Berkshire’s chairman and chief executive officer, is famous for buying during declines, saying he’s betting on the long-term health of the U.S. economy. Berkshire’s holding in Delta swelled to about 71.9 million shares with the Feb. 27 purchases, the filing shows.