Almost 2 million workers can be described as "second job entrepreneurs." They have primary positions in wage-and-salary jobs and hold second jobs as self-employed workers in unincorporated businesses.
The median age of second job entrepreneurs in 1998 was about 43 years, nearly 4 years older than the median for all workers. The largest proportion of second job entrepreneurs was the 35-to 44-year-old group—over a third were in this age group.
Over 75 percent of all second job entrepreneurs worked their second jobs in one of four occupational groups: executive, administrative, and managerial; professional specialty; farming, forestry, and fishing; or sales occupations. In comparison, about 44 percent of all workers are in these occupations.
Bureau of Labor Statistics, U.S. Department of Labor, The Economics Daily, Working for someone else and for yourself at https://www.bls.gov/opub/ted/1999/sept/wk1/art03.htm (visited December 09, 2023).