Initial claims for unemployment insurance caused by mass layoff events -- where 50 or more workers are laid off from a single workplace -- rose in January from December 2010, but fell compared to a year ago, the U.S. Bureau of Labor Statistics reported today.

On a seasonally adjusted basis, 149,799 initial claims for unemployment insurance related to mass layoffs were filed in January. That's up 8.6 percent from December 2010, but down 12.7 percent from January 2010.

The number of mass layoff events -- 1,534 in January -- was up 3.4 percent from the December 2010 and down 10.6 percent from January 2010.

The industry with the most initial claims for unemployment insurance resulting from mass layoffs in January was "temporary help services" at 20,948, according to numbers that were not seasonally adjusted. "School and employee bus transportation" posted the second-highest number at 14754.