In every decennial census from 1880 to 1990, immigrants are more likely to be self-employed than natives. Impressionistic data indicate that immigrant firms are usually quite small and tend to employ co-ethnics and family. Nevertheless, they are sufficiently powerful in the aggregate to have revitalized many neighborhoods, particularly in hard-hit urban areas. There are great variations in the self-employment rates of different immigrant and ethnic groups. Researchers disagree about the reason for this variation, with some proposing that it is the result of the human or financial capital of individual immigrants, and others suggesting that immigrant communities are themselves differential sources of entrepreneurial energy.
Researchers also disagree about the nature and potential of the immigrant firm.