Measuring mercantile concentration in eighteenth-century British America: Charleston, 1735–1775

In this article, the authors attempt to advance discussions of mercantile concentration in British North America in the eighteenth century by employing two measurement tools common in the field of industrial organization-concentration ratios and the Hirschman-Herfindahl Index (HHI)—to measure and analyze concentration levels in Charleston, South Carolina between 1735 and 1775. These tools allow for the creation of standardized measures, easing comparisons with other mercantile groups across space and time. The principal results suggest that mercantile concentration levels in Charleston were not high by modern standards, and that concentration may even have declined a bit over the course of this 41-year period. The authors draw on insights from the literature in industrial organization and the new institutional history to explain their findings. In so doing, they suggest that the relatively low levels of concentration were related to and reflected the “open-access order” characteristic of British North America, even in eighteenth-century South Carolina.