The financial crisis took its toll on the US defence sector on Thursday as Lockheed Martin slashed its 2009 earnings forecast for a second time and Northrop Grumman warned it would report a loss for 2008 due to a writedown of up to $3.4bn.

Lockheed, the world’s largest defence contractor, cut its full-year earnings forecast to $7.05-$7.25 per share, from the $7.65-$7.90 per share it projected in October and below analysts’ expectations of about $7.85 per share.