Abstract
A hallmark of the modern age is the expanded use of informal communication methods in professional and business relationships. Based upon theoretical insights from the organisational permeability and boundary literature, we develop and test a set of hypotheses exploring the changing nature of communication patterns between the purchasing function and its internal and external partners. Our results suggest that while external communications tend to have higher levels of formality than those with internal partners, both internal and external communication patterns trend towards less formality over time, with external formality dropping more markedly than internal formality. Furthermore, we find that trends in formal and informal communication patterns influence perceptions of supplier performance.