From 1992 to 2009, the percentage that firms in any given size class contributed to net employment change was similar to the average employment share of that size class, with the exception of the second quarter, 2001 through second quarter, 2003 period.
For example, firms with 50 to 99 employees accounted for between 8.2 percent and 9.5 percent of the net jobs gained or lost, while their average employment shares ranged from 8.2 percent to 8.5 percent.
Firms with 1,000 or more employees accounted for almost half (47.0 percent) of the job losses from the second quarter, 2001, through second quarter, 2003. (During this period, there was a total net job loss of 4.0 million jobs).
During the same period, firms in the 1 to 4 employee size class gained jobs. As a result, their contribution to jobs lost during that period was negative (−3.3 percent). This size class was the only one to have a negative contribution to net jobs lost in this period.
From 1992 to 2009, regardless of the period, average employment shares were stable for each size class.
These data are from the Business Employment Dynamics (BED) program. To learn more, see "Employment growth by size class: firm and establishment data" (PDF), by Sherry Dalton, Erik Friesenhahn, James Spletzer, and David Talan in the December 2011 issue of the Monthly Labor Review. A firm is a legal business, either corporate or otherwise, and may consist of one establishment, a few establishments, or even a very large number of establishments.
Bureau of Labor Statistics, U.S. Department of Labor, The Economics Daily, Firm size and share of employment change, 1992–2009 at https://www.bls.gov/opub/ted/2012/ted_20120113.htm (visited August 15, 2022).