The quest for stylized facts regarding market share and natural market structures is not new, however extant research has predominantly concentrated on share rank and distribution. Using a sample of 220K firm-year observations representative of the US economy over four decades, this study reexamines the relationship between market share and profitability. The results indicate that being ‘stuck in the middle’ is a prevalent and empirically generalizable phenomenon that persists decade after decade even as average industry profitability decreases. Businesses with roughly 3%-11% intermediate market share appear to be stuck in the middle between specialists and generalists and find themselves at significant financial performance disadvantages across industry groups. The relationship consistently follows a non-linear pattern which must be taken into account during research design and sampling.