Northrop Grumman slumps after quarterly profit halves

Shares of defense contractor Northrop Grumman NOC.N fall 10% to $477 premarket

NOC posts 49% drop in Q1 profit from losses on B-21 stealth bomber program due to higher manufacturing costs

Co reports per-share profit of $3.32, compared with the $6.32 it posted a year earlier

NOC posts Q1 sales of $9.47 bln, down 7% from the $10.13 bln it posted a year earlier

As of last close, stock up 13% YTD