Abstract
This article examines practice diffusion in an environment where competing logics exist, specifically investigating how trustee and performance logics that were rooted in different locations (Boston and New York) led to variation in how mutual funds established contracts with independent professional money management firms. This focus on competing logics redirects institutional research away from isomorphism and the segregation of institutional and technical forces and toward an appreciation of how multiple forms of rationality underlie change in organizational fields. Implications for the dominant two-stage institutional model of diffusion and for research on institutions, organizations, and professions are discussed.