Buffett-led Berkshire Hathaway opened a position in Pfizer in the third quarter of 2020. In a regulatory filing last week, though, Berkshire revealed that it had dumped all of its shares in the big drugmaker.. Pfizer won emergency use authorization (EUA) for COVID-19 vaccine Comirnaty (BNT162b2) in the U.S. and in Europe. It lined up […]