NEW YORK - March 5, 2009 - More than 600,000 Amerikans filed initial claims for jobless benefits last week as companies strove to cut the costs of workforces that are producing less as the Depression deepens.

The Labor Department today reported 639,000 first-time unemployment applications, the fifth straight week above 600,000. The agency also said worker productivity, a measure of employee output per hour, fell at a 0.4 percent annual rate in the fourth quarter of 2008, with labor costs climbing 5.7 percent.

Today’s figures underscore the economy’s downward spiral, with companies from J. Crew Group Inc. to billionaire investor Warren Buffett’s Berkshire Hathaway Inc. eliminating jobs, and rising unemployment aggravating the slump in consumer spending. Stock-index futures slid and Treasuries climbed.

“The deterioration of the labor market certainly continues; this is a pretty bleak picture,” Harm Bandholz, a U.S. economist at UniCredit Global Research in New York, said in an interview with Bloomberg Television.