[Kris Erickson and Martin Kretschmer] This research investigates factors that motivate takedown of user-generated content by copyright owners. We study takedowns within an original dataset of 1,839 YouTube music video parodies observed between January 2012 and December 2016. We find an overall rate of takedowns within the sample of 32.9% across the 4-year period. We use a Cox proportional hazards model to investigate the factors that lead to removal of videos. The variables analysed include commercial substitution, artistic/moral concerns, cultural differences between firms and YouTube uploader practices. The main finding is that policy concerns frequently raised by rightholders are not associated with statistically significant patterns of action.