This article investigates how cyclical changes in demand influence the relationship between product differentiation and profitability in producer goods industries. It distinguishes between "postponement" industries where goods are made to order and "speculation" industries where goods are made for stock, and examines differences in the product differentiation-profitability relationship for different types of industries over the business cycle. The findings suggest that sellers resort to price shading during a business slump in postponement industries but not in speculation industries. In postponement industries, the positive relationship between product differentiation expenditures and profitability in peak years disappears in trough years. In speculation industries that sell through merchant wholesalers, manufacturers appear to provide additional services to wholesalers in trough years.