This study investigates the relationship between integrative complexity of managers’ perception of their information environment and the volume, breadth, and balance of their use of information sources. Twenty-nine portfolio managers participated in the study which sampled information processing behavior in their ongoing and actual investment decision making. Integrative complexity scores were obtained using a measure based on hierarchical cluster analysis of the output from a version of Kelly’s (1955) Role Construct Repertory Interview. The results suggest that volume and breadth of information source use in the problem finding phase of the decision making process is positively related to the integrative complexity of information environment perception. At a methodological level, the study underlines the importance of detailed task analysis and task modeling in the study of individual differences.