PurposeIndirect knowledge leakage to rivals located near alliance partners represents a significant risk that has received limited scholarly attention. Hence, the question of how to manage this risk – which the authors term “partner-rival co-location risk” – in nonequity alliances remains unanswered, and this study aims to suggest establishing a steering committee to oversee the partnership.Design/methodology/approachDrawing on the agglomeration economies and alliance governance literatures, the authors develop a set of hypotheses and perform a series of empirical tests on 470 nonequity alliances in the US biopharmaceutical industry.FindingsThe authors propose that there is a positive linkage between partner-rival co-location risk and the formation of a steering committee in a nonequity alliance, which receives strong empirical support. Further, this relationship is significantly moderated by the breadth (alliance scope) but not the depth (reciprocal interdependence) of interaction between the partnering firms.Originality/valueThis paper is a pioneer to shed light on “partner-rival co-location risk” and how partner-rival co-location risk affects the governance decision of whether to establish a steering committee in a nonequity alliance, thus offering important theoretical and practical insights into competition and cooperation in alliance management.