Imitation and diffusion remain central concerns for scholars from diverse disciplines and backgrounds such as economics, organizational sociology, and strategy (see Lieberman & Asaba, 2006; Strang & Soule, 1998; Young, 2009). This research has predominantly focused on the conditions that enable or deter imitation, and to a lesser extent the performance consequences for imitators versus innovators or early entrants. The findings are mixed on the extent to which imitative efforts harm or benefit the performance of early versus later entrants. Moreover, the recent proliferation of open-source strategies calls into question the established wisdom that imitation necessarily harms the performance of innovators. It may thus be time to employ more sophisticated empirical strategies to uncover what drives the strategic dynamics of imitation and diffusion, and to reinvigorate the debate by focusing on the mechanisms that shape imitative behavior and the ensuing competitive dynamics. This symposium brings together three tightly connected papers by authors from a range of backgrounds and vintages, and two discussants who have shaped the debate, to address several questions informed by contemporary empirical research: (1) How and when can an imitative product harm (or improve) the performance of the original? (2) How does the order in which firms expand their scope affect their performance? Is it the case that early entrants benefit and laggards suffer as a result of the bandwagon effect? Relatedly, (3) even if early-mover advantage and laggard costs are found, are these driven by intrinsic benefits of moving early rather than late, or is this a matter of fit where selection drives results instead? (4) What explains an industry’s low deterrence of imitation, followed by vigorous patenting? Beyond shedding light on a set of complementary questions, this symposium aims to identify important areas for future research on imitation and diffusion by distilling key lessons from this literature, from opening the debate on identification and endogeneity in assessing the impacts of early versus late imitation, to articulating the specific mechanisms that underpin firms’ strategic choices in terms of imitation. Selection in Early Mover and Bandwagon Effects: Assessing US Banks' Scope Expansion Payoff Presenter: Nicola Cetorelli; Federal Reserve Bank of New York Presenter: Michael G Jacobides; London Business School An Unintended Consequence of Imitation: Unpacking How and When an Imitative Product can Harm Presenter: Erdem Yilmaz; Department of Management and Technology, Bocconi U. Presenter: Ivana Naumovska; INSEAD Innovation and Imitation: Design in the Global Tire Industry Presenter: Jung Kwan Kim; Temple U. Presenter: Vivek Tandon; Fox School of Business, Temple U. Presenter: Ram Mudambi; Temple U.