Firm Sizes over the business cycle There has been a lot of evidence about the firm size distribution (as measured in employment) being Pareto (see for example Luttmer 2007), but what are the properties of this distribution over the business cycle?
These guys (paper) claim the distribution is still power-law, but steeper in recessions and flatter in booms.

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  While it is well known that the distribution of firm sizes (in the US
  at least) looks like a power law distribution, these guys look at
  whether it changes in shape over the business cycle.
  
  They show that (in log-log space) the distribution is actually a power
  law in both recessions and expansions, but its not the same power law,
  its steeper in recessions and flatter in booms, meaning that large
  firms become relatively larger in booms than in recessions, or
  alternatively that there is  a lot of entry of small firms in booms.