Competition, External Economies of Scale, and Unionized Wage

We provide a rationale for the mixed relationship between product market competition and unionized wage, and more importantly, for a generally unexplained empirical evidence of a positive relationship between product market competition and unionized wage. We show that a higher product market competition decreases (increases) unionized wage if the external scale economies are weak (strong). However, a higher product market competition may decrease or increase the unionized wage if the external scale economies are moderate.