Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We explore aspects of two-part tariff competition between duopolists providing a homogeneous service when consumers differ with respect to their usage levels. Competition in only one price component (the fee or the rate) may allow both firms to enjoy positive profits if the other price component has been set at levels different enough between firms. Fixing one price component alters the nature of competition, indirectly introducing an element of product differentiation. Endogenous market segmentation emerges, with the heavier users choosing the lower rate firm and the lighter users choosing the lower fee firm. When no price component can be negative, competition becomes softer, profits tend to be higher but there is also a disadvantage for the firm that starts with a higher fee than that of its rival.