Zipf distribution of US firm sizes

Analyses of firm sizes have historically used data that included limited sa mples of small firms, data typically described by lognormal distributions. Using data on the entire population of tax-paying firms in the United State s, I show here that the Zipf distribution characterizes firm sizes: the pro bability a firm is larger than size s is inversely proportional to s. These results hold for data from multiple years and for various definitions of f irm size.