Description:The $6.4 billion (520 billion yen) net loss will be Sony's biggest ever, and more than double a forecast the Japanese technology firm made only in February. Sony says the heftier loss comes from a charge of around $3.7 billion (300 billion yen) in additional tax expenses in the U.S., where it's been facing severe conditions in recent years. Analysts were expecting a full-year loss of about $2.6 billion.(1:05)